This application claims priority to Chinese Application No. 201410152642.3, filed on Apr. 16, 2014.
1. Field of the Invention
The present invention generally relates to an optical imaging lens set and an electronic device which includes such optical imaging lens set. Specifically speaking, the present invention is directed to an optical imaging lens set of five lens elements and an electronic device which includes such optical imaging lens set of five lens elements.
2. Description of the Prior Art
In recent years, the popularity of mobile phones and digital cameras makes the sizes of various portable electronic products reduce quickly so does the photography modules. The current trend of research is to develop an optical imaging lens set of a shorter length with uncompromised good quality. The most important characters of an optical imaging lens set are image quality and size.
US patent US200723681 discloses an optical imaging lens set made of five lens elements. But the imaging performance and the suppression for distortion are not good enough, and the total length of the optical imaging lens set is up to 12 mm or more. Such bulky optical imaging lens set is not suitable for an electronic device of small size with length less than 10 mm.
US patent US2007229984 also discloses an optical imaging lens set made of five lens elements. Even though the imaging performance has been improved, and the total length of the optical imaging lens set has been shortened to 8 mm, but the optical imaging lens set is still not suitable for an electronic device.
Therefore, how to reduce the total length of a photographic device, but still maintain good optical performance, is an important research objective.
In the light of the above, the present invention is capable of proposing an optical imaging lens set that is lightweight, and has a low production cost, reduced length, high resolution and high image quality. The optical imaging lens set of five lens elements of the present invention has a first lens element, an aperture stop, a second lens element, a third lens element, a fourth lens element and a fifth lens element sequentially from an object side to an image side along an optical axis.
An optical imaging lens includes: a first, second, third and fourth lens element, the first lens element has an object-side surface with a convex part in a vicinity of the optical axis, the second lens element has an image-side surface with a concave part in a vicinity of its periphery; the third lens element has an image-side surface with a convex part in a vicinity of the optical axis, the fourth lens element has an object-side surface with a concave part in a vicinity of the optical axis; the fifth lens element has an object-side surface with a convex part in a vicinity of the optical axis, wherein the optical imaging lens set does not include any lens element with refractive power other than said first, second, third, fourth and fifth lens elements.
In the optical imaging lens set of five lens elements of the present invention, an air gap G12 along the optical axis is disposed between the first lens element and the second lens element, an air gap G23 along the optical axis is disposed between the second lens element and the third lens element, an air gap G34 along the optical axis is disposed between the third lens element and the fourth lens element, an air gap G45 along the optical axis is disposed between the fourth lens element and the fifth lens element, and the sum of total four air gaps between adjacent lens elements from the first lens element to the fifth lens element along the optical axis is Gaa=G12+G23+G34+G45.
In the optical imaging lens set of five lens elements of the present invention, the first lens element has a first lens element thickness T1 along the optical axis, the second lens element has a second lens element thickness T2 along the optical axis, the third lens element has a third lens element thickness T3 along the optical axis, the fourth lens element has a fourth lens element thickness T4 along the optical axis, the fifth lens element has a fifth lens element thickness T5 along the optical axis, and the total thickness of all the lens elements in the optical imaging lens set along the optical axis is ALT=T1+T2+T3+T4+T5. In addition, the distance between the image-side surface of the fifth lens element to an image plane along the optical axis is BFL (back focal length). Besides, the total length of the optical imaging lens set is TTL, in other words, the distance between the first object-side surface of the first lens element to the image plane along the optical axis is TTL.
In the optical imaging lens set of five lens elements of the present invention, the relationship TTL/G34≦12.0 is satisfied.
In the optical imaging lens set of five lens elements of the present invention, the relationship 8.0≦TTL/T4≦12.0 is satisfied.
In the optical imaging lens set of five lens elements of the present invention, the relationship Gaa/T2≧2.9 is satisfied.
In the optical imaging lens set of five lens elements of the present invention, the relationship 2.6≦Gaa/G23≦4.8 is satisfied.
In the optical imaging lens set of five lens elements of the present invention, the relationship ALT/T4≦5.9 is satisfied.
In the optical imaging lens set of five lens elements of the present invention, the relationship TTL/ALT≧1.7 is satisfied.
In the optical imaging lens set of five lens elements of the present invention, the relationship BFL/T4≧1.4 is satisfied.
In the optical imaging lens set of five lens elements of the present invention, wherein the object-side surface of the fifth lens element further comprises a concave part in a vicinity of its periphery.
In the optical imaging lens set of five lens elements of the present invention, the relationship G34/T2≧1.5 is satisfied.
In the optical imaging lens set of five lens elements of the present invention, the relationship ALT/BFL≦2.1 is satisfied.
In the optical imaging lens set of five lens elements of the present invention, the relationship TTL/Gaa≦5.3 is satisfied.
In the optical imaging lens set of five lens elements of the present invention, the relationship 14.6≦TTL/T2≦22.0 is satisfied.
In the optical imaging lens set of five lens elements of the present invention, the relationship BFL/T2≧4.0 is satisfied.
In the optical imaging lens set of five lens elements of the present invention, the relationship BFL/G34≦2.9 is satisfied.
In the optical imaging lens set of five lens elements of the present invention, the relationship ALT/G23≧5.7 is satisfied.
The present invention also proposes an electronic device which includes the optical imaging lens set as described above. The electronic device includes a case and an image module disposed in the case. The image module includes an optical imaging lens set as described above, a barrel for the installation of the optical imaging lens set, a module housing unit for the installation of the barrel, a substrate for the installation of the module housing unit, and an image sensor disposed on the substrate and at an image side of the optical imaging lens set.
These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings.
Before the detailed description of the present invention, the first thing to be noticed is that in the present invention, similar (not necessarily identical) elements are labeled as the same numeral references. In the entire present specification, “a certain lens element has negative/positive refractive power” refers to the part in a vicinity of the optical axis of the lens element has negative/positive refractive power. “An object-side/image-side surface of a certain lens element has a concave/convex part” refers to the part is more concave/convex in a direction parallel with the optical axis to be compared with an outer region next to the region. Taking
As shown in
Furthermore, the optical imaging lens set 1 includes an aperture stop (ape. stop) 80 disposed in an appropriate position. In
In the embodiments of the present invention, the optional filter 72 may be a filter of various suitable functions, for example, the filter 72 may be an infrared cut filter (IR cut filter), placed between the fifth lens element 50 and the image plane 71.
Each lens element in the optical imaging lens set 1 of the present invention has an object-side surface facing toward the object side 2 as well as an image-side surface facing toward the image side 3. In addition, each object-side surface and image-side surface in the optical imaging lens set 1 of the present invention has a part in a vicinity of its circular periphery (circular periphery part) away from the optical axis 4 as well as a part in a vicinity of the optical axis (optical axis part) close to the optical axis 4. For example, the first lens element 10 has a first object-side surface 11 and a first image-side surface 12; the second lens element 20 has a second object-side surface 21 and a second image-side surface 22; the third lens element 30 has a third object-side surface 31 and a third image-side surface 32; the fourth lens element 40 has a fourth object-side surface 41 and a fourth image-side surface 42; the fifth lens element 50 has a fifth object-side surface 51 and a fifth image-side surface 52.
Each lens element in the optical imaging lens set 1 of the present invention further has a central thickness on the optical axis 4. For example, the first lens element 10 has a first lens element thickness T1, the second lens element 20 has a second lens element thickness T2, the third lens element 30 has a third lens element thickness T3, the fourth lens element 40 has a fourth lens element thickness T4, and the fifth lens element 50 has a fifth lens element thickness T5. Therefore, the total thickness of all the lens elements in the optical imaging lens set 1 along the optical axis 4 is ALT, ALT=T1+T2+T3+T4+T5.
In addition, between two adjacent lens elements in the optical imaging lens set 1 of the present invention there is an air gap along the optical axis 4. For example, an air gap G12 is disposed between the first lens element 10 and the second lens element 20, an air gap G23 is disposed between the second lens element 20 and the third lens element 30, an air gap G34 is disposed between the third lens element 30 and the fourth lens element 40, and an air gap G45 is disposed between the fourth lens element 40 and the fifth lens element 50. Therefore, the sum of total four air gaps between adjacent lens elements from the first lens element 10 to the fifth lens element 50 along the optical axis 4 is Gaa, Gaa=G12+G23+G34+G45.
Besides, the total length of the optical imaging lens set is TTL, in other words, the distance between the first object-side surface 11 of the first lens element 10 to the image plane 71 along the optical axis 4 is TTL; the distance between the fifth image-side surface 52 of the fifth lens element 50 to the image plane 71 along the optical axis 4 is BFL.
Please refer to
The optical imaging lens set 1 of the first example has five lens elements 10 to 50, and all of the lens elements are made of a plastic material and have refractive power. The optical imaging lens set 1 also has an aperture stop 80, a filter 72, and an image plane 71. The aperture stop 80 is provided between the first lens element 10 and the second lens element 20. The filter 72 may be an infrared filter (IR cut filter) to prevent inevitable infrared light from reaching the image plane to adversely affect the imaging quality.
The first lens element 10 has positive refractive power. The first object-side surface 11 facing toward the object side 2 is a convex surface, having a convex part 13 in the vicinity of the optical axis and a convex part 14 in a vicinity of its circular periphery; The first image-side surface 12 facing toward the image side 3 is a convex surface, having a concave part 16 in the vicinity of the optical axis and a convex part 17 in a vicinity of its circular periphery.
The second lens element 20 has negative refractive power. The second object-side surface 21 facing toward the object side 2 has a convex part 23 in the vicinity of the optical axis and a convex part 24 in a vicinity of its circular periphery; The second image-side surface 22 facing toward the image side 3 has a concave part 26 in the vicinity of the optical axis and a concave part 27 in a vicinity of its circular periphery.
The third lens element 30 has positive refractive power. The third object-side surface 31 facing toward the object side 2 is a concave surface, having a concave part 33 in the vicinity of the optical axis and a concave part 34 in a vicinity of its circular periphery; The third image-side surface 32 facing toward the image side 3 is a convex surface, having a convex part 36 in the vicinity of the optical axis and a convex part 37 in a vicinity of its circular periphery.
The fourth lens element 40 has positive refractive power. The fourth object-side surface 41 facing toward the object side 2 is a concave surface and the fourth image-side surface 42 facing toward the image side 3 is a concave surface, having a concave part 43 in the vicinity of the optical axis and a concave part 44 in a vicinity of its circular periphery; The fourth image-side surface 42 facing toward the image side 3 is a convex surface, having a convex part 46 in the vicinity of the optical axis and a convex part 47 in a vicinity of its circular periphery.
The fifth lens element 50 has negative refractive power, a fifth object-side surface 51 facing toward the object side 2 and a fifth image-side surface 52 facing toward the image side 3. The fifth object-side surface 51 has a convex part 53 in the vicinity of the optical axis and a concave part 54 in a vicinity of its circular periphery. The fifth image-side surface 52 has a concave part 56 in the vicinity of the optical axis and a convex part 57 in a vicinity of its circular periphery. The filter 72 may be an infrared cut filter, and is disposed between the fifth lens element 50 and the image plane 71.
In the optical imaging lens element 1 of the present invention, the object-side surfaces 11/21/31/41/51 and image-side surfaces 12/22/32/42/52 are all aspherical. These aspheric coefficients are defined according to the following formula:
In which:
R represents the curvature radius of the lens element surface;
Z represents the depth of an aspherical surface (the perpendicular distance between the point of the aspherical surface at a distance Y from the optical axis and the tangent plane of the vertex on the optical axis of the aspherical surface);
Y represents a vertical distance from a point on the aspherical surface to the optical axis;
K is a conic constant; and
a2i is the aspheric coefficient of the 2i order.
The optical data of the first example of the optical imaging lens set 1 are shown in
Please refer to
It is worth nothing, compared with the first example, this example has some advantages such as having shorter total length, being easier to produce and having higher yield.
Please refer to
It is worth nothing, compared with the first example, this example has some advantages such as having better imaging quality and better suppression for distortion, being easier to produce and having higher yield.
Please refer to
It is worth nothing, compared with the first example, this example has some advantages such as having better imaging quality and better suppression for distortion, being easier to produce and having higher yield.
Please refer to
It is worth nothing, compared with the first example, this example has some advantages such as having better imaging quality, being easier to produce and having higher yield.
Please refer to
It is worth nothing, compared with the first example, this example has some advantages such as having larger aperture so as to improve the dark shooting performance, being easier to produce and having higher yield.
Please refer to
It is worth nothing, compared with the first example, this example has some advantages such as having larger aperture so as to improve the dark shooting performance, having better imaging quality, being easier to produce and having higher yield.
Following is the definitions of each parameter mentioned above and some other parameters which are not disclosed in the examples of the present invention, shown as TABLE 1:
The applicant summarized the efficacy of each embodiment mentioned above as follows:
In the present invention, all of the longitudinal spherical aberration, the astigmatism aberration and the distortion are in compliance with the using standard. In addition, the off-axis light of red, blue and green wavelengths are focused on the vicinity of the imaging point in different height, therefore the deviation between each off-axis light and the imaging point is well controlled, so as to have good suppression for spherical aberration, aberration and distortion. Furthermore, the curves of red, blue and green wavelengths are very close to each other, meaning that the dispersion on the axis has greatly improved too. In summary, the different lens elements of the present invention are matched to each other, to achieve good image quality.
In addition, the inventors discover that there are some better ratio ranges for different data according to the above various important ratios are shown as below in TABLE 2. Better ratio ranges help the designers to design the better optical performance and an effectively reduced length of a practically possible optical imaging lens set.
It is worth noting that, in views of the unpredictability of the optical system design, under the structure of the invention, by controlling the parameters, can help the designer to design the optical imaging lens set with good optical performance, has shorter total length and being feasible in manufacturing process. Each parameter has its preferred range. TABLE 2 shows the preferred range lower limit and range upper limit of each relationship mentioned in the present invention.
The optical imaging lens set 1 of the present invention may be applied to a portable electronic device. Please refer to
As shown in
The image sensor 70 used here is a product of chip on board (COB) package rather than a product of the conventional chip scale package (CSP) so it is directly attached to the substrate 172, and protective glass is not needed in front of the image sensor 70 in the optical imaging lens set 1, but the present invention is not limited to this.
To be noticed in particular, the optional filter 72 may be omitted in other examples although the optional filter 72 is present in this example. The case 110, the barrel 130, and/or the module housing unit 140 may be a single element or consist of a plurality of elements, but the present invention is not limited to this.
Each one of the five lens elements 10, 20, 30, 40 and 50 with refractive power is installed in the barrel 130 with air gaps disposed between two adjacent lens elements in an exemplary way. The module housing unit 140 has a lens element housing 141, and an image sensor housing 146 installed between the lens element housing 141 and the image sensor 70. However in other examples, the image sensor housing 146 is optional. The barrel 130 is installed coaxially along with the lens element housing 141 along the axis I-I′, and the barrel 130 is provided inside of the lens element housing 141.
Because the optical imaging lens set 1 of the present invention may be as short as about 3.8 mm, this ideal length allows the dimensions and the size of the portable electronic device 100 to be smaller and lighter, but excellent optical performance and image quality are still possible. In such a way, the various examples of the present invention satisfy the need for economic benefits of using less raw materials in addition to satisfy the trend for a smaller and lighter product design and consumers' demands.
Please also refer to
The first seat element 142 may pull the barrel 130 and the optical imaging lens set 1 which is disposed inside of the barrel 130 to move along the axis I-I′, namely the optical axis 4 in
Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.
Number | Date | Country | Kind |
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201410152642.3 | Apr 2014 | CN | national |