(12) United States Patent (10) Patent N0.: US 8,314,999 B1 Tsai (45) Date of Patent: Nov. 20, 2012

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1 US0083 l4999bl (12) United States Patent (10) Patent N0.: US 8,314,999 B1 Tsai (45) Date of Patent: Nov. 20, 2012 (54) OPTICAL IMAGE LENS ASSEMBLY (58) Field Of Classi?cation Search /715, _ 359/771, 772, 775 (75) Inventor: TSllng-Hall TSai, Talchllng (TW) See application?le for complete search history. (73) Assignee: Largan Precision Co., Ltd., Taichung (56) References Cited (TW) U.S. PATENT DOCUMENTS ( ) Notice. Subject to any disclaimer, the term ofth1s 7,145,736 B2 12/2006 Noda patent is extended or adjusted under 35 7,365,920 B2 4/2008 Noda U.S.C. 154(b) by 0 days. _ Primary Examiner * Jack Dinh (21) App1_ NO; 13/226,505 (74) Attorney, Agent, or Firm * CKC & Partners Co., Ltd. (22) Filed: Sep. 7, 2011 (57) ABSTRACT (30) Foreign Application Priority Data An optical image lens assembly includes, in order from an object side to an image side, a?rst lens element With positive refractive power and having a convex object-side surface, a May 16, 2011 (TW) ~~~~~~~~~~~~~~~~~~~~~~~~~~~ A second lens element With negative refractive power, a third lens element With negative refractive power and having a (51) Int- Cl- convex object-side surface and a concave image-side surface, G02B 3/02 ( ) and a fourth lens element With refractive power and having a G02B 9/34 ( ) concave image-side surface. G02B 9/36 ( ) (52) US. Cl /715; 359/772; 359/ Claims, 16 Drawing Sheets 11}

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1 OPTICAL IMAGE LENS ASSEMBLY RELATED APPLICATIONS The application claims priority to TaiWan Application Serial Number 100117102,?led May 16, 2011, Which is herein incorporated by reference.

18 1 OPTICAL IMAGE LENS ASSEMBLY RELATED APPLICATIONS The application claims priority to TaiWan Application Serial Number ,?led May 16, 2011, Which is herein incorporated by reference. BACKGROUND 1. Technical Field The present invention relates to an optical image lens assembly. More particularly, the present invention relates to a compact optical image lens assembly applicable to electronic products. 2. Description of Related Art In recent years, With the popularity of mobile products With camera functionalities, the demand for compact optical image lens assemblies is increasing. The sensor of a conven tional photographing camera is typically a CCD (Charge Coupled Device) image sensor or a CMOS (Complementary Metal-Oxide-Semiconductor) sensor. As advanced semicon ductor manufacturing technologies have allowed the pixel size of sensors to be reduced and compact optical image lens assemblies have gradually evolved toward higher megapix els, there is an increasing demand for compact optical image lens assemblies featuring better image quality. A conventional compact optical image lens assembly in a portable electronic product typically utilizes a three-element lens structure. Such a conventional optical image lens assem bly has a?rst lens element With positive refractive power, a second lens element With negative refractive power and a third lens element With positive refractive power. The?rst, second and third lens elements are arranged in this order from an obj ect-side to an image-side. While the three-element lens structure is compact, it is not able to produce high quality images. Another conventional compact optical image lens assem bly provides a four-element lens structure. The?rst lens ele ment and the second lens element of the four-element lens structure are two glass spherical lens elements Which are attached to each other to form a doublet lens for eliminating chromatic aberration. HoWever, this lens structure requires a longer total optical track length caused by insuf?cient degrees of freedom in setting system parameters due to too many spherical lenses allocated. Moreover, it is not easy to attach the glass lenses, and thus the manufacturing process for form ing the glass doublet lenses is dif?cult. SUMMARY According to one aspect of the present disclosure, an opti cal image lens assembly includes, in order from an object side to an image side, a?rst lens element, a second lens element, a third lens element and a fourth lens element. The?rst lens element With positive refractive power has a convex object side surface. The second lens element has negative refractive power. The third lens element With negative refractive power has a convex object-side surface and a concave image-side surface. The third lens element is made of plastic material, and the object-side surface and the image-side surface of the third lens element are aspheric. The fourth lens element With refractive power has a concave image- side surface. The fourth lens element is made of plastic material, and the object-side surface and the image-side surface of the fourth lens element are aspheric. When an axial distance between the second lens element and the third lens element is T23, an axial distance US 8,314,999 B between the third lens element and the fourth lens element is T34, a focal length of the optical image lens assembly is f, and a focal length of the third lens element is f3, the following relationships are satis?ed: According to another aspect of the present disclosure, an optical image lens assembly includes, in order from an object side to an image side, a?rst lens element, a second lens element, a third lens element and a fourth lens element. The?rst lens element With positive refractive power has a convex object-side surface. The second lens element has negative refractive power. The third lens element With negative refrac tive power has a convex object-side surface and a concave image-side surface. The third lens element is made of plastic material and the object-side surface and the image-side sur face of the third lens element are aspheric. The fourth lens element With refractive power has a concave image-side sur face. The fourth lens element is made of plastic material and the object-side surface and the image-side surface of the fourth lens element are aspheric. When an axial distance between the second lens element and the third lens element is T23, an axial distance between the third lens element and the fourth lens element is T34, a focal length of the second lens element is f2, a focal length of the third lens element is f3, the Abbe number of the second lens element is V2, and the Abbe number of the third lens element is V3, the following rela tionships are satis?ed: BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of an optical image lens assem bly according to the?rst embodiment of the present disclo sure; FIG. 2 shows spherical aberration curves, astigmatic?eld curves and a distortion curve of the optical image lens assem bly according to the?rst embodiment; FIG. 3 is a schematic view of an optical image lens assem bly according to the second embodiment of the present dis closure; FIG. 4 shows spherical aberration curves, astigmatic?eld curves and a distortion curve of the optical image lens assem bly according to the second embodiment; FIG. 5 is a schematic view of an optical image lens assem bly according to the third embodiment of the present disclo sure; FIG. 6 shows spherical aberration curves, astigmatic?eld curves and a distortion curve of the optical image lens assem bly according to the third embodiment; FIG. 7 is a schematic view of an optical image lens assem bly according to the fourth embodiment of the present disclo sure; FIG. 8 shows spherical aberration curves, astigmatic?eld curves and a distortion curve of the optical image lens assem bly according to the fourth embodiment; FIG. 9 is a schematic view of an optical image lens assem bly according to the?fth embodiment of the present disclo sure;

3 FIG. 10 shows spherical aberration curves, astigmatic?eld curves and a distortion curve of the optical image lens assem bly according to the?fth embodiment; FIG.

19 3 FIG. 10 shows spherical aberration curves, astigmatic?eld curves and a distortion curve of the optical image lens assem bly according to the?fth embodiment; FIG. 11 is a schematic view of an optical image lens assem bly according to the sixth embodiment of the present disclo sure; FIG. 12 shows spherical aberration curves, astigmatic?eld curves and a distortion curve of the optical image lens assem bly according to the sixth embodiment; FIG. 13 is a schematic view of an optical image lens assem bly according to the seventh embodiment of the present dis closure; FIG. 14 shows spherical aberration curves, astigmatic?eld curves and a distortion curve of the optical image lens assem bly according to the seventh embodiment; FIG. 15 is a schematic view of an optical image lens assem bly according to the eighth embodiment of the present dis closure; and FIG. 16 shows spherical aberration curves, astigmatic?eld curves and a distortion curve of the optical image lens assem bly according to the eighth embodiment. DETAILED DESCRIPTION An optical image lens assembly includes, in order from an object side to an image side, a?rst lens element, a second lens element, a third lens element and a fourth lens element. The optical image lens assembly further includes an image sensor located on the image plane. The?rst lens element With positive refractive power pro vides partial refractive power for reducing the total track length of the optical image lens assembly. The?rst lens ele ment has a convex obj ect-side surface, and can have a convex image-side surface or a concave image-side surface. When the?rst lens element has a convex object-side surface and a convex image-side surface, the refractive power thereof can be effectively enhanced, thus further reducing the total track length of the optical image lens assembly. When the?rst lens element has a convex object-side surface and a concave image-side surface, the astigmatism of the optical image lens assembly can be is corrected. The second lens element With negative refractive power can correct the aberration generated from the?rst lens ele ment and the chromatic aberration of the optical image lens assembly. The third lens element With negative refractive power can cooperate With the second lens element for reducing the pho tosensitivity of the optical image lens assembly. The third lens element has a convex object-side surface and a concave image-side surface so that the back focal length of the optical image lens assembly can be increased, thereby ensuring that there is a su?icient back focal length for the disposing of other elements. The fourth lens element has a concave image-side surface so that the principal point of the optical image lens assembly can be positioned away from the image plane, and the total track length of the optical image lens assembly can be reduced so as to maintain the compact size of the optical image lens assembly. The fourth lens element can have a convex obj ect-side surface for correcting the astigmatism and the high-order aberration. Furthermore, the fourth lens ele ment can have positive refractive power or negative refractive power. When the fourth lens element has positive refractive power, the high-order aberration of the optical image lens assembly can be further corrected While enhancing the resolving power thereof. When the fourth lens element has negative refractive power, the principal point of the optical US 8,314,999 B image lens assembly can be further positioned away from the image plane. Moreover, the fourth lens element has at least one in?ection point formed on at least one of the obj ect-side surface and the image-side surface thereof. Therefore, the incident angle of the off-axis?eld of light on the image sensor can be effectively minimized and the aberration of the off axis?eld can be corrected. When an axial distance between the second lens element and the third lens element is T23, and an axial distance between the third lens element and the fourth lens element is T34, the following relationship is satis?ed: Therefore, the arrangement of the third lens element can further reduce the track focal length of the optical image lens assembly. T23 and T34 can further satisfy the following rela tionship: When a focal length of the optical image lens assembly is f, and a focal length of the third lens element is f3, the following relationship is satis?ed: Therefore, the focal length of the third lens element can reduce the photo sensitivity of the optical image lens assembly effectively. f and f3 can further satisfy the following relationship: Moreover, f and 13 can further satisfy the following rela tionship: When the focal length of the second lens element is f2, and the focal length of the third lens element is f3, the following relationship is satis?ed: Therefore, the refractive power of the second lens element can be controlled for reducing the photosensitivity of the optical image lens assembly. f2 and f3 can further satisfy the following relationship: When the Abbe number of the second lens element is V2, and the Abbe number of the third lens element is V3, the following relationship is satis?ed: Therefore, the ability for correcting the chromatic aberra tion of the optical image lens assembly can be enhanced. When the focal length of the optical image lens assembly is f, and the focal length of the second lens element is f2, the following relationship is satis?ed: Therefore, the focal length of the second lens element can correct the aberration of the optical image lens assembly. When the focal length of the optical image lens assembly is f, and a focal length of the?rst lens element is f1, the follow ing relationship is satis?ed: Therefore, the total track length of the optical image lens assembly can be controlled by the refractive power of the?rst lens element, and the spherical aberration thereof can also be avoided.

5 When the focal length of the optical image lens assembly is f, and a curvature radius of the image- side surface of the third lens element is R6, the following relationship is satis?

20 5 When the focal length of the optical image lens assembly is f, and a curvature radius of the image- side surface of the third lens element is R6, the following relationship is satis?ed: Therefore, the curvature of the image-side surface of the third lens element can correct the astigmatism of the optical image lens assembly. When the Abbe number of the?rst lens element is V1, and the Abbe number of the second lens element is V2, the fol lowing relationship is satis?ed: Therefore, the ability for correcting the chromatic aberra tion of the optical image lens assembly can be enhanced. When a curvature radius of the object-side surface of the?rst lens element is R1, and the focal length of the optical image lens assembly is f, the following relationship is satis?ed: Therefore, the total track length of optical image lens assembly can be further reduced so as to maintain the com pact size thereof. When a half of a diagonal length of an effective photosen sitive area of the image sensor is Imgh, and an axial distance between the obj ect-side surface of the?rst lens element and the image plane is TTL, the following relationship is satis?ed: Therefore, the total track length of the optical image lens assembly can be reduced, so as to maintain the compact size of the optical image lens assembly. As a result, the optical image system may be applied to lightweight and portable electronic products. According to the optical image lens assembly of the present disclosure, When the lens element has a convex sur face, this indicates that the paraxial region of the surface is convex, and When the lens element has a concave surface, this indicates that the paraxial region of the surface is concave. According to the optical image lens assembly of the present disclosure, the lens element can be made of glass material or plastic material. When the lens element is made of glass material, the range over Which the refractive power of the optical image lens assembly can be set may be increased. When the lens element is made of plastic material, the cost of manufacture can be effectively reduced. Moreover, the sur face of the lens element can be aspheric, so that it is easier to make the surface into other non-spherical shapes. As a result, more controllable variables are obtained, the aberration is reduced and the number of required lens elements is reduced. Therefore, the total track length of the optical image lens assembly can be reduced. According to the optical image lens assembly of the present disclosure, the optical image lens assembly can include at least one stop for reducing stray light While retain ing high image quality, such as an aperture stop. Furthermore, the position of an aperture stop Within the optical image lens assembly can be arbitrarily placed in front of the entire optical image lens assembly or Within the optical image lens assem bly depending on the preference of the designer of the optical system, in order to achieve the desirable optical features or higher image quality produced from the optical image lens assembly. According to the above description of the present inven tion, the following lst-8th speci?c embodiments are provided for further explanation. US 8,314,999 B FIG. 1 is a schematic view of an optical image lens assem bly according to to the?rst embodiment of the present dis closure. FIG. 2 shows spherical aberration curves, astigmatic?eld curves and a distortion curve of the optical image lens assembly according to the?rst embodiment. In FIG. 1, the optical image lens assembly includes, in order from an object side to an image side, an aperture stop 100, the?rst lens element 110, the second lens element 120, the is third lens element 130, the fourth lens element 140, an IR (infrared) cut?lter 160 and an image plane 150. The?rst lens element 110 is made of plastic material. The?rst lens element 110 With positive refractive power has a convex obj ect-side surface 111 and a convex image-side sur face 112. The object-side surface 111 and the image-side surface 112 of the?rst lens element 110 are aspheric. The second lens element 120 is made of plastic material. The second lens element 120 With negative refractive power has a concave object-side surface 121 and a concave image side surface 122. The object-side surface 121 and the image side surface 122 of the second lens element 120 are aspheric. The third lens element 130 is made of plastic material. The third lens element 130 With negative refractive power has a convex object-side surface 131 and a concave image-side surface 132. The object-side surface 131 and the image-side surface 132 of the third lens element 130 are aspheric. The fourth lens element 140 is made of plastic material. The fourth lens element 140 With positive refractive power has a convex object-side surface 141 and a concave image side surface 142. The object-side surface 141 and the image side surface 142 of the fourth lens element 140 are aspheric. Moreover, the fourth lens element 140 has in?ection points formed on both the object-side surface 141 and the image side surface 142 thereof. The IR cut?lter 160 is made of glass and located between the fourth lens element 140 and the image plane 150, and Will not affect the focal length of the optical image lens assembly. The equation of the aspheric surface pro?les of the afore mentioned lens elements of the?rst embodiment is expressed as follows: Where: X is the height of a point on the aspheric surface spaced at a distance Y from the optical axis relative to the tangential plane at the aspheric surface vertex; Y is the distance from the point on the curve of the aspheric surface to the optical axis; R is the curvature radius of the surface of the lens element; k is the conic coe?icient; and Ai is the i-th aspheric coe?icient. In the optical image lens assembly according to the?rst embodiment, When f is a focal length of the optical image lens assembly, Fno is an f-number of the optical image lens assem bly, and HFOV is half of the maximal?eld of view, these parameters have the following values: f:3.38 mm; Fno:2.80; and HFOV:33.5 degrees. In the optical image lens assembly according to the?rst embodiment, When the Abbe number of the?rst lens element

(12) Patent Application Publication (10) Pub. No.: US 2013/ A1

(19) United States US 20130279021A1 (12) Patent Application Publication (10) Pub. No.: US 2013/0279021 A1 CHEN et al. (43) Pub. Date: Oct. 24, 2013 (54) OPTICAL IMAGE LENS SYSTEM Publication Classification