The present invention relates to an optical lens, especially to an optical lens with smaller volume and better image quality.
In recent years, while technology of smart phones and hand-held tablet computers has greatly advanced, the requirements for optical image qualities of image-capturing devices of various mobile devices have increased as well. In addition, due to the thinning designs of mobile devices, the thickness of the optical lens of an image-capturing device has to be thinned accordingly. An optical lens is normally formed of several lenses. In order to increase the competitive advantages in the market, it has always been a pursuit in product developments to achieve size reduction, high image quality, and reduced manufacturing cost.
Therefore, it is in need to provide novel optical lenses having reduced sizes and improved image qualities with reduced costs.
The present invention is related to an optical lens having a reduced size and a good image quality with a reduced cost.
One embodiment of the present invention provides an optical lens. The optical lens includes, in order from an object side to an image-forming side: a first lens group having positive refractive power and a second lens group having negative refractive power. The first lens group includes, in order from the object side to the image-forming side, a first lens having refractive power and a second lens having refractive power. The second lens group includes, in order from the object side to the image-forming side, a third lens having refractive power and a fourth lens having refractive power. The optical lens satisfies at least one of the following conditions: a thickness of the first lens group is less than a first distance between the first lens group and the second lens group; and |δ7/D4|≥2 wherein a second distance between a projected position which an effective diameter of an object-side surface of the fourth lens projected on an optical axis and a first intersection point which the object-side surface of the fourth lens and the optical axis is δ7, and a thickness of the fourth lens is D4.
Another embodiment of the present invention provides an optical lens. The optical lens includes, in order from an object side to an image-forming side: a first lens, a second lens, a third lens and a fourth lens. The first lens has positive refractive power, and a first thickness of the first lens is D1. The second lens has refractive power, a second thickness of the second lens is D2, and a distance between an image-forming side of the first lens and an object-side surface of the second lens is D12. The third lens has refractive power, and a first distance between an image-forming side of the second lens and an object-side surface of the third lens is D23. The fourth lens has refractive power, a thickness of the fourth lens is D4, and a second distance between a projected position which an effective diameter of an object-side surface of the fourth lens projected on an optical axis and a first intersection point which the object-side surface of the fourth lens and the optical axis is δ7. The optical lens satisfies at least one of the following conditions: (D1+D12+D2)≤D23 and |δ7/D4|≥2.
A further embodiment of the present invention provides an optical lens. The optical lens includes, in order from an object side to an image-forming side: a first lens, a second lens, a third lens, and a fourth lens. The first lens may have positive refractive power, the second lens may have refractive power, the third lens may be a concave-convex lens, and the fourth lens may be a concave lens.
By the features described above, the present invention provides a zoom lens having light weight, high zoom ratio, and good image quality with reduced cost.
The embodiments of the present invention are described in details with reference to the accompanying drawings. While the invention will be described in conjunction with these specific embodiments, it will be understood that it is not intended to limit the invention to these embodiments. On the contrary, it is intended to cover alternatives, modifications, and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. The present invention may be practiced without some or all of these specific details. In other instances, well-known components and process operations are not described in detail in order not to unnecessarily obscure the present invention. Identical or similar elements of the embodiments are designated with the same or similar reference numerals. While drawings are illustrated in details, it is appreciated that the quantity or sizes of the disclosed components may be greater or less than that disclosed, except expressly restricting the amount or the sizes of the components.
As shown in
In one embodiment, the first lens group G1 having positive refractive power is arranged with the second lens group G2 having negative refractive power.
Moreover, an object-side surface S8 of the fourth lens L4 is a concave surface curving toward the image-forming side. Particularly, the object-side surface S8 close to the optical axis OA has negative refractive power.
In one embodiment, the optical lens OL1 may satisfy the following conditions:
0.1<|F1/F2| and/or |F1/F2|<0.5;
wherein F1 is focal length of the first lens L1, and F2 is the focal length of the second lens L2.
In addition, in one embodiment, the optical lens OL1 may further satisfy the following conditions:
−0.12<1/(F12+F34−D23) and/or 1/(F12+F34−D23)<0;
wherein F12 is a focal length of the first lens group G1, F34 is a focal length of the second lens group G2, and D23 is a distance between an image-forming side of the first lens group G1 and an object side of the second lens group G2. Specifically speaking, F12 is a total focal length of the first lens L1 and the second lens L2, F34 is a total focal length of the third lens L3 and the fourth lens L4, and D23 is a distance between an image-side surface S5 of the second lens L2 and an object-side surface S6 of the third lens L3. The image-side surface S5 of the second lens L2 is substantially equivalent to the surface “S5” in table 1 and table 3, and the object-side surface S6 of the third lens L3 is substantially equivalent to the surface “S6” in table 1 and table 3.
In one embodiment of the optical lens OL1, a first distance between the first lens group G1 and the second lens group G2 is larger than a thickness of the first lens group G1. That is, the optical lens OL1 may further satisfy the following condition:
the thickness of the first lens group G1 is less than the first distance between the first lens group G1 and the second lens group G2.
That is, the thickness of the first lens group G1<D23.
Wherein, D23 is a first distance between the image-forming side of the first lens group G1 and the object-side surface of the second lens group G2. As shown in
In one embodiment, along the optical axis, the thickness of the first lens group G1 is less than the first distance between the first lens group G1 and the second lens group G2.
In other words, refer to
(D1+D12+D2)≤D23 and (D1+D12+D2)−D23≤0
wherein D1 is a thickness of the first lens L1, D2 is a thickness of the first lens L2, and D12 is a distance between the image-forming side of the first lens L1 and the object-side surface of the second lens L2.
As shown in
In one embodiment, the optical lens OL1 may further satisfy the following condition:
|h8/H8|<0.4.
Specifically speaking, the infection point IF is located on the image-side surface S9 of the fourth lens L4 from adjacent to the optical axis OA to the lens edge, and the second distance H8 may be the effective aperture of the fourth lens L4. The image-side surface S9 of the fourth lens L4 is substantially equivalent to the surface “S9” in table 1 and table 3.
Moreover, as shown in
In one embodiment, the optical lens OL1 may further satisfy at least one of the following condition: |δ7/D4|≥2, |δ7/D4|≥2.5, |δ7/D4|≥3, |δ7/D4|≥3.5, |δ7/D4|≥4, |δ7/D4|≥4.5 and |δ7/D4|≥4.8.
In another embodiment, the optical lens OL1 may further satisfy the following condition:
|δ8/D4|<0.22.
Specifically speaking, in the optical lens OL1 of the embodiment, the image-side surface S9 of the fourth lens L4 is aspheric. The image-side surface S9 extends, along the direction from the outer edge to the optical axis OA, toward the image-forming side of the optical lens OL1 and then reversely toward the object side of the optical lens OL1. Accordingly, the infection point IF of the fourth lens L4 is substantially the position, located on the image-side surface S9 of the fourth lens L4, being closest to the imaging-plane I.
In one embodiment, the signs of refractive powers of the first lens L1, the second lens L2, the third lens L3, and the fourth lens L4 are in staggered arrangement.
For example, the first lens L1 has positive refractive power, the second lens L2 has negative refractive power, the third lens L3 has positive refractive power, and the fourth lens L4 has negative refractive power.
In an embodiment, at least one of the first lens L1, the second lens L2, the third lens L3, and the fourth lens L4 may be an aspheric lens or a free-form lens, the aspheric lens has at least one aspheric surface, and the free-form lens has at least one free-form surface.
In another embodiment, the first lens L1, the second lens L2, the third lens L3, and the fourth lens L4 may all be aspheric lenses, each of the aspheric lenses has at least one aspheric surface, and each of the aspheric surfaces may satisfy the following equation:
where Z is the coordinate in the optical axis OA direction, and the direction of the light propagation is designated as positive; A4, A6, A8, A10, A12, and A14 are aspheric coefficients; K is coefficient of quadratic surface; C is reciprocal of R (C=1/R); R is the radius of curvature; Y is the coordinate in a direction perpendicular to the optical axis OA, in which the upward direction away from the optical axis OA is designated as positive. In addition, each of the parameters or the coefficients of the equation of each of the aspheric lenses may be designated respectively to determine the focal length of each of the aspheric lenses.
Besides, in one embodiment, the first lens L1, the second lens L2, the third lens L3, and the fourth lens L4 may all be plastic lenses. The material of the plastic lenses may include, but not limited to, polycarbonate, cyclic olefin copolymer (e.g. APEL), polyester resins (e.g. OKP4 or OKP4HT), or a mixture material including at least one of the above-mentioned three materials.
In one embodiment, the object-side surface S1 and the image-side surface S2 of the first lens L1 may both be aspheric. As shown in
In one embodiment, as shown in
In one embodiment, as shown in
In one embodiment, as shown in
Moreover, as shown in
Table 1 lists the detail information of the optical lens OL1 according to an embodiment of this invention. The detail information includes the curvature radius, the thickness, the refractive index, and the Abbe number of each of the lenses, where the surface numbers of the first lens group G1 and the second lens group G2 are sequentially ordered from the object side to the image-forming side. For example, “S1” stands for the object-side surface S1 of the first lens L1, “S2” stands for the image-side surface S2 of the first lens L1, “S3” stands for the stop St, and “S10” and “S11” respectively stand for the object-side surface S10 and the image-side surface S11 of the filter F. In addition, the “thickness” stands for the distance between an indicated surface and an adjacent surface close to the image-forming side. For example, the thickness of the surface S1 indicated in table 1 is the distance between the surface S1 and the surface S2.
In one embodiment as shown in
Table 3 lists the detail information of the optical lens OL2 according to one embodiment as shown in
In one embodiment as shown in
As shown in
While the invention has been described by way of example and in terms of the preferred embodiments, it is to be understood that the invention is not limited thereto. On the contrary, it is intended to cover various modifications, equivalents, and similar arrangements and procedures, and the scope of the invention is intended to be limited solely by the appended claims.
Number | Date | Country | Kind |
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104107565 A | Mar 2015 | TW | national |
This application is a continuation-in-part application of co-pending application Ser. No. 14/963,232, filed on Dec. 8, 2015, which claims the benefit of Taiwan application Serial No. 104107565, filed Mar. 10, 2015, the subject matter of which is incorporated herein by reference.
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20150130992 | Hsu et al. | May 2015 | A1 |
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Number | Date | Country |
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2013-92584 | May 2013 | JP |
Entry |
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Chinese Office Action dated Dec. 28, 2017. |
Number | Date | Country | |
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20180172951 A1 | Jun 2018 | US |
Number | Date | Country | |
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Parent | 14963232 | Dec 2015 | US |
Child | 15896022 | US |