Optical imaging lens

An optical imaging lens may include a first, a second, a third and a fourth lens elements positioned in an order from an object side to an image side. Through designing concave and/or convex surfaces of the four lens elements, the optical imaging lens may provide improved imaging quality and optical characteristics, increased field of view and increased aperture while the optical imaging lens may satisfy (G34+T4)/AAG≤2.200 and V1+V2+V3+V4≥110.000, wherein an air gap between the third lens element and the fourth lens element along the optical axis is represented by G34, a thickness of the fourth lens element along the optical axis is represented by T4, a sum of the three air gaps from the first lens element to the fourth lens element along the optical axis is represented by AAG and Abbe numbers of the first to the fourth lens elements are represented by V1, V2, V3 and V4.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to P.R.C. Patent Application No. 201811623272.1 titled “Optical Imaging Lens,” filed on Dec. 28, 2018, with the State Intellectual Property Office of the People's Republic of China (SIPO).

TECHNICAL FIELD

The present disclosure relates to an optical imaging lens, and particularly, to an optical imaging lens having four lens elements.

BACKGROUND

Technology improves every day, continuously expanding consumer demand for increasingly compact electronic devices. As a result, key components of optical imaging lenses that are incorporated into consumer electronic products should keep pace with technological improvements in order to meet the expectations of consumers. Some important characteristics of an optical imaging lens include image quality and size. In response to the environment with insufficient light, there may also be demands for an increased field of view and a large aperture. As image sensor technology improves, consumers' expectations related to image quality have also risen. Accordingly, in addition to reducing the size of the imaging lens, achieving good optical characteristics and performance should also be considered.

Decreasing the dimensions of an optical lens while maintaining good optical performance might not be achieved simply by scaling down the lens. Rather, these benefits may be realized by improving other aspects of the design process, such as by varying the material used for the lens or adjusting the assembly yield.

In this manner, there is a continuing need for improving the design characteristics of optical lenses that have increasingly reduced the dimensions. Achieving these advancements may entail overcoming unique challenges, even when compared to design improvements for traditional optical lenses. However, refining aspects of the optical lens manufacturing process that result in a lens that meets consumer demands and provides upgrades to imaging quality continues to be a desirable objective for industries, governments, and academia.

SUMMARY

In light of the abovementioned problems, the optical imaging lens having good imaging quality, a shortened length, increased field of view and increased aperture is the point of improvement.

The present disclosure provides an optical imaging lens for capturing images and videos such as the optical imaging lens of cell phones, cameras, tablets and personal digital assistants, and car lenses. By controlling the convex or concave shape of the surfaces of four lens elements, the size of the optical imaging lens may be reduced and field of view of the optical imaging lens may be extended while maintaining good optical characteristics.

In the specification, parameters used herein may include:

ParameterDefinitionT1A thickness of the first lens element along the optical axisG12A distance from the image-side surface of the first lens element to the object-sidesurface of the second lens element along the optical axis, i.e., an air gap betweenthe first lens element and the second lens element along the optical axisT2A thickness of the second lens element along the optical axisG23A distance from the image-side surface of the second lens element to the object-side surface of the third lens element along the optical axis, i.e., an air gapbetween the second lens element and the third lens element along the optical axisT3A thickness of the third lens element along the optical axisG34A distance from the image-side surface of the third lens element to the object-sidesurface of the fourth lens element along the optical axis, i.e., an air gap betweenthe third lens element and the fourth lens element along the optical axisT4A thickness of the fourth lens element along the optical axisG4FA distance from the image-side surface of the fourth lens element to the object-side surface of the filtering unit along the optical axis, i.e., an air gap between thefourth lens element and the filtering unit along the optical axisTTFA thickness of the filtering unit along the optical axisGFPA distance from the image-side surface of the filtering unit to the image planealong the optical axis, i.e., an air gap between the filtering unit and the imageplane along the optical axisf1A focal length of the first lens elementf2A focal length of the second lens elementf3A focal length of the third lens elementf4A focal length of the fourth lens elementn1A refractive index of the first lens elementn2A refractive index of the second lens elementn3A refractive index of the third lens elementn4A refractive index of die fourth lens elementV1An Abbe number of the first lens elementV2An Abbe number of the second lens elementV3An Abbe number of the third lens elementV4An Abbe number of the fourth lens elementHFOVHalf Field of View of the optical imaging lensFnoF-number of the optical imaging lensEFLAn effective focal length of the optical imaging lensTTLA distance from the object-side surface of the first lens element to the imageplane along the optical axis, i.e., the length of the optical imaging lensALTA sum of the thicknesses of four lens elements from the first lens element to thefourth lens element along the optical axis, i.e., a sum of the thicknesses of the firstlens element, the second lens element, the third lens element and the fourth lenselement along the optical axisAAGA sum of the three air gaps from the first lens element to the fourth lens elementalong the optical axis, i.e., a sum of the a distance from the image-side surface ofthe first lens element to the object-side surface of the second lens element alongthe optical axis, a distance from the image-side surface of the second lens elementto the object-side surface of the third lens element along the optical axis, and adistance from the image-side surface of the third lens element to the object-sidesurface of the fourth lens element along the optical axis.BFLA back focal length of the optical imaging lens, i.e., a distance from the image-side surface of the fourth lens element to the image plane along the optical axisTLA distance from the object-side surface of the first lens element to the image-sidesurface of the fourth lens element along the optical axisTminThe minimum of the four thicknesses from the first lens element to the fourth lenselement along the optical axisTmaxThe maximum of the four thicknesses from the first lens element to the fourthlens elements along the optical axisGminThe minimum of the three air gaps from the first lens element to the fourth lenselement along the optical axisGmaxThe maximum of the three air gaps from the first lens element to the fourth lenselement along the optical axisImgHAn image height of the optical imaging lens

According to an embodiment of the optical imaging lens of the present disclosure, an optical imaging lens may comprise a first lens element, a second lens element, a third lens element and a fourth lens element sequentially from an object side to an image side along an optical axis. The first lens element to the fourth lens element may each comprise an object-side surface facing toward the object side and allowing imaging rays to pass through and an image-side surface facing toward the image side and allowing the imaging rays to pass through. The first lens element may have negative refracting power. The second lens element may have positive refracting power. A periphery region of the object-side surface of the second lens element may be concave. An optical axis region of the image-side surface of the second lens element may be concave. An optical axis region of the object-side surface of the third lens element may be concave. An optical axis region of the image-side surface of the fourth lens element may be concave. The optical imaging lens may comprise no other lenses having refracting power beyond the four lens elements. The optical imaging lens may satisfy Inequalities:
(G34+T4)/AAG≤2.200   Inequality (1); and
V1+V2+V3+V4≥110.000   Inequality (2).

According to another embodiment of the optical imaging lens of the present disclosure, an optical imaging lens may comprise a first lens element, a second lens element, a third lens element and a fourth lens element sequentially from an object side to an image side along an optical axis. The first lens element to the fourth lens element may each comprise an object-side surface facing toward the object side and allowing imaging rays to pass through and an image-side surface facing toward the image side and allowing the imaging rays to pass through. The first lens element may have negative refracting power. A periphery region of the image-side surface of the first lens element may be convex. The second lens element may have positive refracting power. A periphery region of the object-side surface of the second lens element may be concave. An optical axis region of the image-side surface of the second lens element may be concave. An optical axis region of the image-side surface of the fourth lens element may be concave. The optical imaging lens may comprise no other lenses having refracting power beyond the four lens elements. The optical imaging lens may satisfy Inequalities:
(G34+T4)/AAG≤2.200   Inequality (1); and
V1+V2+V3+V4≥110.000   Inequality (2).

In some example embodiments, more details about the convex or concave surface structure, refracting power or chosen material etc. could be incorporated for one specific lens element or broadly for a plurality of lens elements to improve the control for the system performance and/or resolution. It is noted that the details listed herein could be incorporated into the example embodiments if no inconsistency occurs.

Through controlling the convex or concave shape of the surfaces and at least one inequality, the optical imaging lens in the example embodiments may achieve good imaging quality, the length of the optical imaging lens may be effectively shortened, and field of view and aperture of the optical imaging lens may be extended.

DETAILED DESCRIPTION

For a more complete understanding of the present disclosure and its advantages, reference is now made to the following description taken in conjunction with the accompanying drawings, in which like reference numbers indicate like features. Persons having ordinary skill in the art will understand other varieties for implementing example embodiments, including those described herein. The drawings are not limited to specific scale and similar reference numbers are used for representing similar elements. As used in the disclosures and the appended claims, the terms “example embodiment,” “exemplary embodiment,” and “present embodiment” do not necessarily refer to a single embodiment, although it may, and various example embodiments may be readily combined and interchanged, without departing from the scope or spirit of the present disclosure. Furthermore, the terminology as used herein is for the purpose of describing example embodiments only and is not intended to be a limitation of the disclosure. In this respect, as used herein, the term “in” may include “in” and “on”, and the terms “a”, “an” and “the” may include singular and plural references. Furthermore, as used herein, the term “by” may also mean “from”, depending on the context. Furthermore, as used herein, the term “if” may also mean “when” or “upon”, depending on the context. Furthermore, as used herein, the words “and/or” may refer to and encompass any and all possible combinations of one or more of the associated listed items.

In the present disclosure, the optical system may comprise at least one lens element to receive imaging rays that are incident on the optical system over a set of angles ranging from parallel to an optical axis to a half field of view (HFOV) angle with respect to the optical axis. The imaging rays pass through the optical system to produce an image on an image plane. The term “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 term “an object-side (or image-side) surface of a lens element” refers to a specific region of that surface of the lens element at which imaging rays can pass through that specific region. Imaging rays include at least two types of rays: a chief ray Lc and a marginal ray Lm (as shown inFIG. 1). An object-side (or image-side) surface of a lens element can be characterized as having several regions, including an optical axis region, a periphery region, and, in some cases, one or more intermediate regions, as discussed more fully below.

FIG. 1is a radial cross-sectional view of a lens element100. Two referential points for the surfaces of the lens element100can be defined: a central point, and a transition point. The central point of a surface of a lens element is a point of intersection of that surface and the optical axis I. As illustrated inFIG. 1, a first central point CP1may be present on the object-side surface110of lens element100and a second central point CP2may be present on the image-side surface120of the lens element100. The transition point is a point on a surface of a lens element, at which the line tangent to that point is perpendicular to the optical axis I. The optical boundary OB of a surface of the lens element is defined as a point at which the radially outermost marginal ray Lm passing through the surface of the lens element intersects the surface of the lens element. All transition points lie between the optical axis I and the optical boundary OB of the surface of the lens element. If multiple transition points are present on a single surface, then these transition points are sequentially named along the radial direction of the surface with reference numerals starting from the first transition point. For example, the first transition point, e.g., TP1, (closest to the optical axis I), the second transition point, e.g., TP2, (as shown inFIG. 4), and the Nth transition point (farthest from the optical axis I).

The region of a surface of the lens element from the central point to the first transition point TP1is defined as the optical axis region, which includes the central point. The region located radially outside of the farthest Nth transition point from the optical axis I to the optical boundary OB of the surface of the lens element is defined as the periphery region. In some embodiments, there may be intermediate regions present between the optical axis region and the periphery region, with the number of intermediate regions depending on the number of the transition points.

The shape of a region is convex if a collimated ray being parallel to the optical axis I and passing through the region is bent toward the optical axis I such that the ray intersects the optical axis I on the image side A2of the lens element. The shape of a region is concave if the extension line of a collimated ray being parallel to the optical axis I and passing through the region intersects the optical axis I on the object side A1of the lens element.

Additionally, referring toFIG. 1, the lens element100may also have a mounting portion130extending radially outward from the optical boundary OB. The mounting portion130is typically used to physically secure the lens element to a corresponding element of the optical system (not shown). Imaging rays do not reach the mounting portion130. The structure and shape of the mounting portion130are only examples to explain the technologies, and should not be taken as limiting the scope of the present disclosure. The mounting portion130of the lens elements discussed below may be partially or completely omitted in the following drawings.

Referring toFIG. 2, optical axis region Z1is defined between central point CP and first transition point TP1. Periphery region Z2is defined between TP1and the optical boundary OB of the surface of the lens element. Collimated ray211intersects the optical axis I on the image side A2of lens element200after passing through optical axis region Z1, i.e., the focal point of collimated ray211after passing through optical axis region Z1is on the image side A2of the lens element200at point R inFIG. 2. Accordingly, since the ray itself intersects the optical axis I on the image side A2of the lens element200, optical axis region Z1is convex. On the contrary, collimated ray212diverges after passing through periphery region Z2. The extension line EL of collimated ray212after passing through periphery region Z2intersects the optical axis I on the object side A1of lens element200, i.e., the focal point of collimated ray212after passing through periphery region Z2is on the object side A1at point M inFIG. 2. Accordingly, since the extension line EL of the ray intersects the optical axis I on the object side A1of the lens element200, periphery region Z2is concave. In the lens element200illustrated inFIG. 2, the first transition point TP1is the border of the optical axis region and the periphery region, i.e., TP1is the point at which the shape changes from convex to concave.

Alternatively, there is another way for a person having ordinary skill in the art to determine whether an optical axis region is convex or concave by referring to the sign of “Radius” (the “R” value), which is the paraxial radius of shape of a lens surface in the optical axis region. The R value 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, a positive R value defines that the optical axis region of the object-side surface is convex, and a negative R value defines that the optical axis region of the object-side surface is concave. Conversely, for an image-side surface, a positive R value defines that the optical axis region of the image-side surface is concave, and a negative R value defines that the optical axis region of the image-side surface is convex. The result found by using this method should be consistent with the method utilizing intersection of the optical axis by rays/extension lines mentioned above, which determines surface shape by referring to whether the focal point of a collimated ray being parallel to the optical axis I is on the object-side or the image-side of a lens element. As used herein, the terms “a shape of a region is convex (concave),” “a region is convex (concave),” and “a convex- (concave-) region,” can be used alternatively.

FIG. 3,FIG. 4andFIG. 5illustrate examples of determining the shape of lens element regions and the boundaries of regions under various circumstances, including the optical axis region, the periphery region, and intermediate regions as set forth in the present specification.

FIG. 3is a radial cross-sectional view of a lens element300. As illustrated inFIG. 3, only one transition point TP1appears within the optical boundary OB of the image-side surface320of the lens element300. Optical axis region Z1and periphery region Z2of the image-side surface320of lens element300are illustrated. The R value of the image-side surface320is positive (i.e., R>0). Accordingly, the optical axis region Z1is concave.

In general, the shape of each region demarcated by the transition point will have an opposite shape to the shape of the adjacent region(s). Accordingly, the transition point will define a transition in shape, changing from concave to convex at the transition point or changing from convex to concave. InFIG. 3, since the shape of the optical axis region Z1is concave, the shape of the periphery region Z2will be convex as the shape changes at the transition point TP1.

FIG. 4is a radial cross-sectional view of a lens element400. Referring toFIG. 4, a first transition point TP1and a second transition point TP2are present on the object-side surface410of lens element400. The optical axis region Z1of the object-side surface410is defined between the optical axis I and the first transition point TP1. The R value of the object-side surface410is positive (i.e., R>0). Accordingly, the optical axis region Z1is convex.

The periphery region Z2of the object-side surface410, which is also convex, is defined between the second transition point TP2and the optical boundary OB of the object-side surface410of the lens element400. Further, intermediate region Z3of the object-side surface410, which is concave, is defined between the first transition point TP1and the second transition point TP2. Referring once again toFIG. 4, the object-side surface410includes an optical axis region Z1located between the optical axis I and the first transition point TP1, an intermediate region Z3located between the first transition point TP1and the second transition point TP2, and a periphery region Z2located between the second transition point TP2and the optical boundary OB of the object-side surface410. Since the shape of the optical axis region Z1is designed to be convex, the shape of the intermediate region Z3is concave as the shape of the intermediate region Z3changes at the first transition point TP1, and the shape of the periphery region Z2is convex as the shape of the periphery region Z2changes at the second transition point TP2.

FIG. 5is a radial cross-sectional view of a lens element500. Lens element500has no transition point on the object-side surface510of the lens element500. For a surface of a lens element with no transition point, for example, the object-side surface510the lens element500, the optical axis region Z1is defined as the region between 0-50% of the distance between the optical axis I and the optical boundary OB of the surface of the lens element and the periphery region is defined as the region between 50%-100% of the distance between the optical axis I and the optical boundary OB of the surface of the lens element. Referring to lens element500illustrated inFIG. 5, the optical axis region Z1of the object-side surface510is defined between the optical axis I and 50% of the distance between the optical axis I and the optical boundary OB. The R value of the object-side surface510is positive (i.e., R>0). Accordingly, the optical axis region Z1is convex. For the object-side surface510of the lens element500, because there is no transition point, the periphery region Z2of the object-side surface510is also convex. It should be noted that lens element500may have a mounting portion (not shown) extending radially outward from the periphery region Z2.

According to an embodiment of the optical imaging lens of the present disclosure, an optical imaging lens may comprise a first lens element, a second lens element, a third lens element and a fourth lens element sequentially from an object side to an image side along an optical axis. The first lens element to the fourth lens element may each comprise an object-side surface facing toward the object side and allowing imaging rays to pass through and an image-side surface facing toward the image side and allowing the imaging rays to pass through. By designing the following detail features of four lens elements incorporated one another, the length of the optical imaging lens may be effectively shortened, and field of view and aperture of the optical imaging lens may be effectively extended while maintaining good optical characteristics.

In some embodiments of the optical imaging lens of the present disclosure, the first lens element having negative refracting power may be beneficial for extending the field of view of the optical imaging lens. The second lens element having positive refracting power and a periphery region of the object-side surface of the second element being concave may be beneficial for gather large-angle light. An optical axis region of the image-side surface of the second lens element being concave may be beneficial for correcting aberration generated from the first lens element. An optical axis region of the image-side surface of the fourth lens element being concave may be beneficial for correcting local aberration.

Moreover, the optical imaging lens satisfying an Inequality (1), (G34+T4)/AAG≤2.200, may be beneficial for reducing the length of the optical imaging lens and extending the field of view of the optical imaging lens. The further restrictions for Inequality (1) that may constitute better configuration are as follows: 0.200≤(G34+T4)/AAG≤2.200. Further, the optical imaging lens satisfying an Inequality (2), V1+V2+V3+V4≥110.000, may be beneficial for correcting chromatic aberration of the optical system and reducing the length of the optical imaging lens, and the further restrictions for Inequality (2) that may constitute better configuration are as follows: 110.000≤V1+V2+V3+V4 194.000.

Optionally, an optical axis region of the object-side surface of the third lens element being concave may be beneficial for correcting aberration generated from the first lens element and the second lens element. Optionally, a periphery region of the image-side surface of the first lens element being convex may be beneficial for achieving better optical performance.

According to some embodiments of the optical imaging lens the present disclosure, selectively designing the optical imaging lens in accordance with the following Inequalities may assist the designer in designing an optical imaging lens that has good optical performance, is effectively shortened in overall length, and is technically feasible.

In some embodiments of the optical imaging lens of the present disclosure, in addition to Inequalities (1) and (2), the optical imaging lens may satisfy at least one of Inequalities (5), (6), (9), (14), (15), (17)-(20) for decreasing the length of the optical imaging lens and improving the imaging quality thereof by adjusting air gaps between the lens elements or thicknesses of the lens elements along the optical axis. Since the difficulty of manufacture and the optical performance may also be considered, the air gaps between the lens elements or thicknesses of the lens elements along the optical axis need to be mutually allocated, or the ratio of value combination for specific optical parameters in the specific lens group. The further restrictions for Inequalities (5), (6), (14), (15), (17)-(20) defined below may constitute better configuration:
0.400≤AAG/T1≤1.600;
0.200≤ALT/EFL≤1.300;
0.200≤AAG/(T1+T2)≤1.000;
0.800≤BFL/T3≤1.800;
1.100≤(T3+G34+T4)/(T1+G12)≤2.800;
1.200≤ALT/(T2+T3)≤1.800;
1.000≤AAG/G23 1.900;
1.000≤(T2+G23+T3)/(T1+T4)≤2.600; and
0.400≤(T1+T2)/T3≤1.200.

In some embodiments of the optical imaging lens of the present disclosure, the optical imaging lens may satisfy at least one of Inequalities (3), (4), (7), (10), (12), (13) and (16), such that the ratio between optical imaging lens parameters of the optical element and the length of the optical imaging lens (TTL) may have appropriate values. The further restrictions for Inequalities (3), (4), (7), (10), (12), (13) and (16) defined below may prevent optical imaging lens parameters that are too large to allow the length of the optical imaging lens to be sufficiently shortened, and prevent optical imaging lens parameters that are too small to interfere with assembly of the optical imaging lens:
0.900≤TTL/EFL≤2.500;
1.300≤TL/BFL≤2.600;
1.300≤TL/(G23+T3)≤2.400;
1.200≤TTL/(T1+G12+T2+G23+T3)≤2.000;
0.600≤TL/EFL≤1.700;
1.200≤TTL/ImgH≤2.400;
0.900≤TL/ImgH1.800.

Since shortened EFL may be beneficial for extending the field of view of the optical imaging lens in some embodiments of the present disclosure, EFL should be shortened and the optical imaging lens may satisfy Inequality (11) for extending the field of view of the optical imaging lens during slimming the optical system. Moreover, the further restrictions for Inequality (11) defined below may constitute better configuration: 1.100≤EFL/BFL≤2.200.

Since increased ImgH may be beneficial for improving optical performance in some embodiments of the present disclosure, ImgH should be increased and the optical imaging lens may satisfy Inequalities (4), (8) and (13) for improving imaging sharpness during slimming the optical system. Moreover, the further restrictions for Inequality Inequalities (4), (8) and (13) defined below may constitute better configuration:
1.200≤TTL/ImgH≤2.400;
0.900≤TL/ImgH≤1.800; and
1.100≤(ALT+BFL)/ImgH≤2.100.

In addition, any combination of the parameters of the embodiment may be selected to increase the optical imaging lens limitation to facilitate the optical imaging lens design of the same architecture of the present invention. In consideration of the non-predictability of design for the optical system, while the optical imaging lens may satisfy any one of inequalities described above, the optical imaging lens according to the disclosure herein may achieve a shortened length and an extended field of view, provide an increased aperture, improve an imaging quality and/or assembly yield, and/or effectively improve drawbacks of a typical optical imaging lens.

Several exemplary embodiments and associated optical data will now be provided to illustrate non-limiting examples of optical imaging lens systems having good optical characteristics, an increased aperture and an extended field of view. Reference is now made toFIGS. 6-9.FIG. 6illustrates an example cross-sectional view of an optical imaging lens1having four lens elements according to a first example embodiment.FIG. 7shows example charts of a longitudinal spherical aberration and other kinds of optical aberrations of the optical imaging lens1according to the first example embodiment.FIG. 8illustrates an example table of optical data of each lens element of the optical imaging lens1according to the first example embodiment.FIG. 9depicts an example table of aspherical data of the optical imaging lens1according to the first example embodiment.

As shown inFIG. 6, the optical imaging lens1of the present embodiment, in an order from an object side A1tan image side A2along an optical axis, may comprise an aperture stop STO, a first lens element L1, a second lens element L2, a third lens element L3and a fourth lens element L4. A filtering unit TF and an image plane IMA of an image sensor (not shown) may be positioned at the image side A2of the optical imaging lens1. Each of the first, second, third and fourth lens elements L1, L2, L3and L4, and the filtering unit TF may comprise an object-side surface L1A2/L2A1/L3A1/L4A1/TFA1facing toward the object side A1and an image-side surface L1A2/L2A2/L3A2/L4A2/TFA2facing toward the image side A2. The example embodiment of the illustrated filtering unit TF may be positioned between the fourth lens element L4and the image plane IMA. The filtering unit TF may be a filter for preventing unwanted light from reaching the image plane IMA and affecting imaging quality.

Exemplary embodiments of each lens element of the optical imaging lens1will now be described with reference to the drawings. The lens elements L1, L2, L3and L4of the optical imaging lens1may be constructed using plastic materials in this embodiment.

An example embodiment of the first lens element L1may have negative refracting power. The optical axis region L1A1C of the object-side surface L1A1of the first lens element L1may be convex. The periphery region L1A1P of the object-side surface L1A1of the first lens element L1may be concave. The optical axis region L1A2C of the image-side surface L1A2of the first lens element L1may be concave. The periphery region L1A2P of the image-side surface L1A2of the first lens element L1may be convex.

An example embodiment of the second lens element L2may have positive refracting power. The optical axis region L2A1C of the object-side surface L2A1of the second lens element L2may be convex. The periphery region L2A1P of the object-side surface L2A1of the second lens element L2may be concave. The optical axis region L2A2C of the image-side surface L2A2of the second lens element L2may be concave. The periphery region L2A2P of the image-side surface L2A2of the second lens element L2may be convex.

An example embodiment of the third lens element L3may have positive refracting power. The optical axis region L3A1C of the object-side surface L3A1of the third lens element L3may be concave. The periphery region L3A1P of the object-side surface L3A1of the third lens element L3may be convex. Both of the optical axis region L3A2C and the periphery region L3A2P of the image-side surface L3A2of the third lens element L3may be convex.

An example embodiment of the fourth lens element L4may have negative refracting power. The optical axis region L4A1C of the object-side surface L4A1of the fourth lens element L4may be convex. The periphery region L4A1P of the object-side surface L4A1of the fourth lens element L4may be concave. The optical axis region L4A2C of the image-side surface L4A2of the fourth lens element L4may be concave. The periphery region L4A2P of the image-side surface L4A2of the fourth lens element L4may be convex.

The aspherical surfaces including the object-side surface L1A1and the image-side surface L1A2of the first lens element L1, the object-side surface L2A1and the image-side surface L2A2of the second lens element L2, the object-side surface L3A1and the image-side surface L3A2of the third lens element L3, the object-side surface L4A1and the image-side surface L4A2of the fourth lens element L4may all be defined by the following aspherical formula (1):

R represents the radius of curvature of the surface of the lens element;

Z represents the depth of the 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 the perpendicular distance between the point of the aspherical surface and the optical axis;

K represents a conic constant; and

a2irepresents an aspherical coefficient of 2ithlevel.

The values of each aspherical parameter are shown inFIG. 9.

FIG. 7(a)shows a longitudinal spherical aberration for three representative wavelengths (920 nm, 940 nm and 960 nm), wherein the vertical axis ofFIG. 7(a)defines the field of view.FIG. 7(b)shows the field curvature aberration in the sagittal direction for three representative wavelengths (920 nm, 940 nm and 960 nm), wherein the vertical axis ofFIG. 7(b)defines the image height.FIG. 7(c)shows the field curvature aberration in the tangential direction for three representative wavelengths (920 nm, 940 nm and 960 nm), wherein the vertical axis ofFIG. 7(c)defines the image height.FIG. 7(d)shows a variation of the distortion aberration, wherein the vertical axis ofFIG. 7(d)defines the image height. The three curves with different wavelengths (920 nm, 940 nm and 960 nm) may represent that off-axis light with respect to these wavelengths may be focused around an image point. From the vertical deviation of each curve shown inFIG. 7(a), the offset of the off-axis light relative to the image point may be within about ±0.02 mm Therefore, the first embodiment may improve the longitudinal spherical aberration with respect to different wavelengths. Referring toFIG. 7(b), the focus variation with respect to the three different wavelengths (920 nm, 940 nm and 960 nm) in the whole field may fall within about ±0.10 mm. Referring toFIG. 7(c), the focus variation with respect to the three different wavelengths (920 nm, 940 nm and 960 nm) in the whole field may fall within about ±0.40 mm Referring toFIG. 7(d), and more specifically the horizontal axis ofFIG. 7(d), the variation of the distortion aberration may be within about ±3%.

The distance from the object-side surface L1A1of the first lens element L1to the image plane IMA along the optical axis (TTL) may be about 4.105 mm, Fno may be about 1.33, HFOV may be about 38.992 degrees, and the effective focal length (EFL) of the optical imaging lens1may be about 2.479 mm. In accordance with these values, the present embodiment may provide an optical imaging lens having a shortened length, an extended field of view and an increased aperture while improving optical performance.

Reference is now made toFIGS. 10-13.FIG. 10illustrates an example cross-sectional view of an optical imaging lens2having four lens elements according to a second example embodiment.FIG. 11shows example charts of a longitudinal spherical aberration and other kinds of optical aberrations of the optical imaging lens2according to the second example embodiment.FIG. 12shows an example table of optical data of each lens element of the optical imaging lens2according to the second example embodiment.FIG. 13shows an example table of aspherical data of the optical imaging lens2according to the second example embodiment.

As shown inFIG. 10, the optical imaging lens2of the present embodiment, in an order from an object side A1to an image side A2along an optical axis, may comprise an aperture stop STO, a first lens element L1, a second lens element L2, a third lens element L3and a fourth lens element L4.

The arrangement of the convex or concave surface structures, including the object-side surfaces L1A1, L2A1, and L4A1and the image-side surfaces L1A2, L2A2, L3A2, and L4A2may be generally similar to the optical imaging lens1, but the differences between the optical imaging lens1and the optical imaging lens2may include the concave or concave surface structures of the object-side surface L3A1, a radius of curvature, a thickness, aspherical data, and/or an effective focal length of each lens element. More specifically, the periphery region L3A1P of the object-side surface L3A1of the third lens element L3of the optical imaging lens2may be concave.

Here, in the interest of clearly showing the drawings of the present embodiment, only the surface shapes which are different from that in the first embodiment may be labeled. Please refer toFIG. 12for the optical characteristics of each lens element in the optical imaging lens2of the present embodiment.

From the vertical deviation of each curve shown inFIG. 11(a), the offset of the off-axis light relative to the image point may be within about ±0.03 mm Referring toFIG. 11(b), the focus variation with respect to the three different wavelengths (920 nm, 940 nm and 960 nm) in the whole field may fall within about ±0.10 mm Referring toFIG. 11(c), the focus variation with respect to the three different wavelengths (920 nm, 940 nm and 960 nm) in the whole field may fall within about ±0.30 mm Referring toFIG. 11(d), the variation of the distortion aberration of the optical imaging lens2may be within about ±3%.

In comparison with the first embodiment, the longitudinal spherical aberration and the field curvature aberration in the tangential direction in the second embodiment may be smaller, and the field of view of the optical imaging lens2may be larger as shown inFIG. 11andFIG. 12. Moreover, the optical imaging lens2may be easier to be manufactured, such that yield thereof may be higher.

Reference is now made toFIGS. 14-17.FIG. 14illustrates an example cross-sectional view of an optical imaging lens3having four lens elements according to a third example embodiment.FIG. 15shows example charts of a longitudinal spherical aberration and other kinds of optical aberrations of the optical imaging lens3according to the third example embodiment.FIG. 16shows an example table of optical data of each lens element of the optical imaging lens3according to the third example embodiment.FIG. 17shows an example table of aspherical data of the optical imaging lens3according to the third example embodiment.

As shown inFIG. 14, the optical imaging lens3of the present embodiment, in an order from an object side A1to an image side A2along an optical axis, may comprise an aperture stop STO, a first lens element L1, a second lens element L2, a third lens element L3and a fourth lens element L4.

The arrangement of the convex or concave surface structures, including the object-side surfaces L2A1, L3A1, and L4A1and the image-side surfaces L1A2, L2A2, L3A2, and L4A2may be generally similar to the optical imaging lens1, but the differences between the optical imaging lens1and the optical imaging lens3may include the concave or concave surface structures of the object-side surface L1A1, a radius of curvature, a thickness, aspherical data, and/or an effective focal length of each lens element. More specifically, the periphery region L1A1P of the object-side surface L1A1of the first lens element L1of the optical imaging lens3may be convex.

Here, in the interest of clearly showing the drawings of the present embodiment, only the surface shapes which are different from that in the first embodiment may be labeled. Please refer toFIG. 16for the optical characteristics of each lens element in the optical imaging lens3of the present embodiment.

From the vertical deviation of each curve shown inFIG. 15(a), the offset of the off-axis light relative to the image point may be within about ±0.03 mm Referring toFIG. 15(b), the focus variation with respect to the three different wavelengths (920 nm, 940 nm and 960 nm) in the whole field may fall within about ±0.10 mm Referring toFIG. 15(c), the focus variation with respect to the three different wavelengths (920 nm, 940 nm and 960 nm) in the whole field may fall within about ±0.40 mm Referring toFIG. 15(d), the variation of the distortion aberration of the optical imaging lens3may be within about ±3%.

In comparison with the first embodiment, the effective focal length of the optical imaging lens3may be shorter be smaller as shown inFIG. 15andFIG. 16. Moreover, the optical imaging lens3may be easier to be manufactured, such that yield thereof may be higher.

Reference is now made toFIGS. 18-21.FIG. 18illustrates an example cross-sectional view of an optical imaging lens4having four lens elements according to a fourth example embodiment.FIG. 19shows example charts of a longitudinal spherical aberration and other kinds of optical aberrations of the optical imaging lens4according to the fourth example embodiment.FIG. 20shows an example table of optical data of each lens element of the optical imaging lens4according to the fourth example embodiment.FIG. 21shows an example table of aspherical data of the optical imaging lens4according to the fourth example embodiment.

As shown inFIG. 18, the optical imaging lens4of the present embodiment, in an order from an object side A1to an image side A2along an optical axis, may comprise a first lens element L1, an aperture stop STO, a second lens element L2, a third lens element L3and a fourth lens element L4.

The arrangement of the convex or concave surface structures, including the object-side surfaces L1A1, L2A1, L3A1, and L4A1and the image-side surfaces L1A2, L2A2, L3A2, and L4A2may be generally similar to the optical imaging lens1, but the differences between the optical imaging lens1and the optical imaging lens4may include the position of the aperture stop STO, a radius of curvature, a thickness, aspherical data, and/or an effective focal length of each lens element. More specifically, the aperture stop STO is arranged between the first lens element L1and the second lens element L2.

Here, in the interest of clearly showing the drawings of the present embodiment, only the surface shapes which are different from that in the first embodiment may be labeled. Please refer toFIG. 20for the optical characteristics of each lens element in the optical imaging lens4of the present embodiment.

From the vertical deviation of each curve shown inFIG. 19(a), the offset of the off-axis light relative to the image point may be within about ±0.12 mm Referring toFIG. 19(b), the focus variation with respect to the three different wavelengths (920 nm, 940 nm and 960 nm) in the whole field may fall within about ±0.12 mm Referring toFIG. 19(c), the focus variation with respect to the three different wavelengths (920 nm, 940 nm and 960 nm) in the whole field may fall within about ±0.16 mm Referring toFIG. 19(d), the variation of the distortion aberration of the optical imaging lens4may be within about ±3%.

In comparison with the first embodiment, the field curvature aberration in the tangential direction in the fourth embodiment may be smaller and the value of the aperture of the optical image lens4may be larger as shown inFIG. 19andFIG. 20. Moreover, the optical imaging lens4may be easier to be manufactured, such that yield thereof may be higher.

Reference is now made toFIGS. 22-25.FIG. 22illustrates an example cross-sectional view of an optical imaging lens5having four lens elements according to a fifth example embodiment.FIG. 23shows example charts of a longitudinal spherical aberration and other kinds of optical aberrations of the optical imaging lens5according to the fifth example embodiment.FIG. 24shows an example table of optical data of each lens element of the optical imaging lens5according to the fifth example embodiment.FIG. 25shows an example table of aspherical data of the optical imaging lens5according to the fifth example embodiment.

As shown inFIG. 22, the optical imaging lens5of the present embodiment, in an order from an object side A1to an image side A2along an optical axis, may comprise an aperture stop STO, a first lens element L1, a second lens element L2, a third lens element L3and a fourth lens element L4.

The arrangement of the convex or concave surface structures, including the object-side surfaces L2A1, L3A1, and L4A1and the image-side surfaces L1A2, L2A2, L3A2, and L4A2may be generally similar to the optical imaging lens1, but the differences between the optical imaging lens1and the optical imaging lens5may include the concave or concave surface structures of the object-side surface L1A1, a radius of curvature, a thickness, aspherical data, and/or an effective focal length of each lens element. More specifically, the periphery region L1A1P of the object-side surface L1A1of the first lens element L1may be convex

Here, in the interest of clearly showing the drawings of the present embodiment, only the surface shapes which are different from that in the first embodiment may be labeled. Please refer toFIG. 24for the optical characteristics of each lens element in the optical imaging lens5of the present embodiment.

From the vertical deviation of each curve shown inFIG. 23(a), the offset of the off-axis light relative to the image point may be within about ±0.02 mm Referring toFIG. 23(b), the focus variation with respect to the three different wavelengths (920 nm, 940 nm and 960 nm) in the whole field may fall within about ±0.04 mm Referring toFIG. 23(c), the focus variation with respect to the three different wavelengths (920 nm, 940 nm and 960 nm) in the whole field may fall within about ±0.08 mm Referring toFIG. 23(d), the variation of the distortion aberration of the optical imaging lens5may be within about ±2%.

In comparison with the first embodiment, the field of view of the optical image lens5may be larger, and the field curvature aberration in the sagittal direction and the tangential direction and the distortion aberration in the fifth embodiment may be smaller as shown inFIG. 23andFIG. 24. Moreover, the optical imaging lens5may be easier to be manufactured, such that yield thereof may be higher.

Reference is now made toFIGS. 26-29.FIG. 26illustrates an example cross-sectional view of an optical imaging lens6having four lens elements according to a sixth example embodiment.FIG. 27shows example charts of a longitudinal spherical aberration and other kinds of optical aberrations of the optical imaging lens6according to the sixth example embodiment.FIG. 28shows an example table of optical data of each lens element of the optical imaging lens6according to the sixth example embodiment.FIG. 29shows an example table of aspherical data of the optical imaging lens6according to the sixth example embodiment.

As shown inFIG. 26, the optical imaging lens6of the present embodiment, in an order from an object side A1to an image side A2along an optical axis, may comprise an aperture stop STO, a first lens element L1, a second lens element L2, a third lens element L3and a fourth lens element L4.

The arrangement of the convex or concave surface structures, including the object-side surfaces L2A1, L3A1, and L4A1and the image-side surfaces L1A2, L2A2, L3A2, and L4A2may be generally similar to the optical imaging lens1, but the differences between the optical imaging lens1and the optical imaging lens6may include the concave or concave surface structures of the object-side surface L1A1, a radius of curvature, a thickness, aspherical data, and/or an effective focal length of each lens element. More specifically, the periphery region L1A1P of the object-side surface L1A1of the first lens element L1of the optical imaging lens6may be convex.

Here, in the interest of clearly showing the drawings of the present embodiment, only the surface shapes which are different from that in the first embodiment may be labeled. Please refer toFIG. 28for the optical characteristics of each lens element in the optical imaging lens6of the present embodiment.

From the vertical deviation of each curve shown inFIG. 27(a), the offset of the off-axis light relative to the image point may be within about ±0.016 mm Referring toFIG. 27(b), the focus variation with respect to the three different wavelengths (920 nm, 940 nm and 960 nm) in the whole field may fall within about ±0.04 mm Referring toFIG. 27(c), the focus variation with respect to the three different wavelengths (920 nm, 940 nm and 960 nm) in the whole field may fall within about ±0.06 mm Referring toFIG. 27(d), the variation of the distortion aberration of the optical imaging lens6may be within about ±1.6%.

In comparison with the first embodiment, the field of view of the optical imaging lens6may be larger, and the longitudinal spherical aberration, the field curvature aberration in the sagittal direction and the tangential direction and the distortion aberration in the sixth embodiment may be smaller as shown inFIG. 27andFIG. 28. Moreover, the optical imaging lens6may be easier to be manufactured, such that yield thereof may be higher.

Reference is now made toFIGS. 30-33.FIG. 30illustrates an example cross-sectional view of an optical imaging lens7having four lens elements according to a seventh example embodiment.FIG. 31shows example charts of a longitudinal spherical aberration and other kinds of optical aberrations of the optical imaging lens7according to the seventh example embodiment.FIG. 32shows an example table of optical data of each lens element of the optical imaging lens7according to the seventh example embodiment.FIG. 33shows an example table of aspherical data of the optical imaging lens7according to the seventh example embodiment.

As shown inFIG. 30, the optical imaging lens7of the present embodiment, in an order from an object side A1to an image side A2along an optical axis, may comprise an aperture stop STO, a first lens element L1, a second lens element L2, a third lens element L3and a fourth lens element L4.

The arrangement of the convex or concave surface structures, including the object-side surfaces L1A1, L2A1, and L4A1and the image-side surfaces L1A2, L2A2, L3A2, and L4A2may be generally similar to the optical imaging lens1, but the differences between the optical imaging lens1and the optical imaging lens7may include the refracting power of the fourth lens element L4, the concave or concave surface structures of the object-side surface L3A1, a radius of curvature, a thickness, aspherical data, and/or an effective focal length of each lens element. More specifically, the periphery region L3A1P of the object-side surface L3A1of the third lens element L3of the optical imaging lens7may be concave, and the fourth lens element L4may have positive refracting power.

Here, in the interest of clearly showing the drawings of the present embodiment, only the surface shapes which are different from that in the first embodiment may be labeled. Please refer toFIG. 32for the optical characteristics of each lens element in the optical imaging lens7of the present embodiment.

From the vertical deviation of each curve shown inFIG. 31(a), the offset of the off-axis light relative to the image point may be within about ±0.01 mm Referring toFIG. 31(b), the focus variation with respect to the three different wavelengths (920 nm, 940 nm and 960 nm) in the whole field may fall within about ±4.00 mm Referring toFIG. 31(c), the focus variation with respect to the three different wavelengths (920 nm, 940 nm and 960 nm) in the whole field may fall within about ±16.00 mm Referring toFIG. 31(d), the variation of the distortion aberration of the optical imaging lens7may be within about ±40%.

In comparison with the first embodiment, the effective focal length of the optical image lens7may be shorter, the field of view of the optical image lens7may be larger, and the longitudinal spherical aberration in the seventh embodiment may be smaller as shown inFIG. 31andFIG. 32. Moreover, the optical imaging lens7may be easier to be manufactured, such that yield thereof may be higher.

Reference is now made toFIGS. 34-37.FIG. 34illustrates an example cross-sectional view of an optical imaging lens8having four lens elements according to an eighth example embodiment.FIG. 35shows example charts of a longitudinal spherical aberration and other kinds of optical aberrations of the optical imaging lens8according to the eighth example embodiment.FIG. 36shows an example table of optical data of each lens element of the optical imaging lens8according to the eighth example embodiment.FIG. 37shows an example table of aspherical data of the optical imaging lens8according to the eighth example embodiment.

As shown inFIG. 34, the optical imaging lens8of the present embodiment, in an order from an object side A1to an image side A2along an optical axis, may comprise an aperture stop STO, a first lens element L1, a second lens element L2, a third lens element L3, and a fourth lens element L4.

The arrangement of the convex or concave surface structures, including the object-side surfaces L1A1, L2A1, L3A1, and L4A1and the image-side surfaces L1A2, L2A2, and L4A2may be generally similar to the optical imaging lens1, but the differences between the optical imaging lens1and the optical imaging lens8may include the concave or concave surface structures of the image-side surface L3A2, a radius of curvature, a thickness, aspherical data, and/or an effective focal length of each lens element. More specifically, the periphery region L3A2P of the image-side surface L3A2of the third lens element L3of the optical imaging lens8may be concave.

Here, in the interest of clearly showing the drawings of the present embodiment, only the surface shapes which are different from that in the first embodiment may be labeled. Please refer toFIG. 36for the optical characteristics of each lens element in the optical imaging lens8of the present embodiment.

From the vertical deviation of each curve shown inFIG. 35(a), the offset of the off-axis light relative to the image point may be within about ±0.10 mm Referring toFIG. 35(b), the focus variation with respect to the three different wavelengths (920 nm, 940 nm and 960 nm) in the whole field may fall within about ±0.40 mm Referring toFIG. 35(c), the focus variation with respect to the three different wavelengths (920 nm, 940 nm and 960 nm) in the whole field may fall within about ±0.40 mm Referring toFIG. 35(d), the variation of the distortion aberration of the optical imaging lens8may be within about ±8%.

In comparison with the first embodiment, the length of the optical imaging lens8may be shorter as shown inFIG. 35andFIG. 36. Moreover, the optical imaging lens8may be easier to be manufactured, such that yield thereof may be higher.

The optical imaging lens in each embodiment of the present disclosure with the arrangements of the convex or concave surface structures described below may advantageously increase the value of HFOV and the aperture with improved imaging quality: the first lens element may have negative refracting power, the second lens element may have positive refracting power, a periphery region of the object-side surface of the second lens element may be concave, an optical axis region of the image-side surface of the second lens element may be concave, and optical axis region of the object-side surface of the third lens element may be concave, an optical axis region of the image-side surface of the fourth lens element may be concave, the optical imaging lens may comprise no other lenses having refracting power beyond the four lens elements, and the optical imaging lens may satisfy Inequality (1): (G34+T4)/AAG≤2.200 and Inequality (2): V1+V2+V3+V4≥110.000. Alternatively, the first lens element may have negative refracting power, a periphery region of the image-side surface of the first lens element may be convex, the second lens element may have positive refracting power, a periphery region of the object-side surface of the second lens element may be concave, an optical axis region of the image-side surface of the second lens element may be concave, an optical axis region of the image-side surface of the fourth lens element may be concave, the optical imaging lens may comprise no other lenses having refracting power beyond the four lens elements, and the optical imaging lens may satisfy Inequality (1): (G34+T4)/AAG≤2.200 and Inequality (2): V1+V2+V3+V4≥110.000.

The range of values within the maximum and minimum values derived from the combined ratios of the optical parameters can be implemented according to above mentioned embodiments.

According to above disclosure, the longitudinal spherical aberration, the field curvature aberration and the variation of the distortion aberration of each embodiment may meet the use requirements of various electronic products which implement an optical imaging lens. Moreover, the off-axis light with respect to 920 nm, 940 nm and 960 nm wavelengths may be focused around an image point, and the offset of the off-axis light for each curve relative to the image point may be controlled to effectively inhibit the longitudinal spherical aberration, the field curvature aberration and/or the variation of the distortion aberration. Further, as shown by the imaging quality data provided for each embodiment, the distance between the 920 nm, 940 nm and 960 nm wavelengths may indicate that focusing ability and inhibiting ability for dispersion may be provided for different wavelengths.

In consideration of the non-predictability of the optical lens assembly, while the optical lens assembly may satisfy any one of inequalities described above, the optical lens assembly herein according to the disclosure may achieve a shortened length and smaller spherical aberration, field curvature aberration, and/or distortion aberration, provide an enlarged field of view, increase an imaging quality and/or assembly yield, and/or effectively improve drawbacks of a typical optical lens assembly.