An optical imaging lens

Abstract

The present invention discloses an optical imaging lens. The lens sequentially includes, from the object side to the image side along its optical axis: a first lens, a diaphragm, a second lens, a third lens, a fourth lens, and a filter. The object-side surface and the image-side surface of all lenses are aspherical surfaces, and the refractive indices of the first lens, the second lens, and the third lens are less than 1.6. The lens satisfies the following relational expressions: (1) -2.9 < f1 / f < -3.5; (2) 3.0 < (f2 + f3) / f < 4.0. The present invention adopts a four-lens structure, and the combination of the surface shape structure and the optimized range of optical parameters of each lens can effectively shorten the overall size of the imaging lens and increase its lens viewing angle while maintaining high imaging quality, and has high resolution brought by high pixels.

Description

Technical Field:

[0001] This invention patent relates to the technical field of photographic lens products, and particularly to an optical imaging lens. Background Art:

[0002] In recent years, with the rise of portable electronic products with photographic functions, the demand for optical systems has been increasing day by day. With the popularization of portable electronic products such as mobile phones and tablet computers, people's need for diversified product functions is increasing. At the same time, with the development of science and technology, imaging technology has become more and more mature and has been widely used in portable electronic products.

[0003] Traditional optical systems mounted on portable devices mostly adopt a three - or four - lens structure. However, since portable devices are constantly developing in the direction of pixel improvement, and the demand of end - consumers for large apertures is also gradually increasing, it is difficult to simultaneously overcome the limitations of wide - angle of view in the environment, miniaturization of the photographic module, and meet the requirements of an optical system for reducing exposure. Therefore, how to effectively increase the viewing wide - angle of an optical imaging lens and further improve the imaging quality has become a very important issue. Summary of the Invention:

[0004] The technical problem to be solved by this invention patent is to overcome the deficiencies of the prior art and provide an optical imaging lens with four lenses.

[0005] To solve the above - mentioned technical problem, this invention patent adopts the following technical solution: An optical imaging lens, which sequentially includes, along its optical axis from the object side to the image side: a first lens with negative refractive power, whose object - side surface near the optical axis is concave; a diaphragm, which is located between the first lens and the second lens; a second lens with positive refractive power, whose object - side surface and image - side surface near the optical axis are both convex; a third lens with positive refractive power; a fourth lens with negative refractive power, whose object - side surface near the optical axis is convex, whose image - side surface near the optical axis is concave, and has at least one convex critical point at the image - side surface far from the optical axis; and a filter and an imaging surface, the filter is located between the fourth lens and the imaging surface; the object - side surfaces and image - side surfaces of all the above lenses are aspherical, and the refractive indices of the first lens, the second lens, and the third lens are less than 1.6; the lens satisfies the following relationships: (1) - 2.9 < f1 / f < - 3.5; (2) 3.0 < (f2 + f3) / f < 4.0.

[0006] Furthermore, in the above - mentioned technical solution, the lens also satisfies the following condition: (3) - 2.0 < f4 / f < 0.0.

[0007] Furthermore, in the above technical solution, the lens further satisfies the following condition: (4) 1.5 < f1 / f4 < 4.5.

[0008] Furthermore, in the above technical solution, the lens further satisfies the following condition: (5) 6.5 <

[0009] (f12 + f34) / f < 8.5.

[0010] Furthermore, in the above technical solution, the lens further satisfies the following condition: (6) 2.0 < ET3 / CT3 < 3.0;

[0011] Furthermore, in the above technical solution, the lens further satisfies the following conditions: (7) 1.2 < ΣCT / f < 2.2; (8) 0 < (CT3 + CT4) / f34 < 1.1; (9) 0.1 < (CT2 + CT3) × T23 < 0.6.

[0012] Furthermore, in the above technical solution, the lens further satisfies the following conditions: (10) 0.0 ≤ (R21 + R22) / (R11 + R12) < 2.2; (11) 0.9 < (R41 + R42) / f < 2.2.

[0013] Furthermore, in the above technical solution, the lens further satisfies the following conditions: (12) 2.0 < TL / ImgH < 2.4; (13) 2.0 < TL / Fno × f < 2.8.

[0014] Furthermore, in the above technical solution, the lens further satisfies the following condition: (14) 35 ≤ V3 - V4.

[0015] Furthermore, in the above technical solution, the lens further satisfies the following condition: (15) The maximum half field of view HFOV of the camera lens group satisfies 49° < HFOV < 58°.

[0016] In the above technical solution, the content represented by each parameter in the corresponding conditions is described later.

[0017] In view of the current requirements for high - standard imaging quality, the present invention features a large aperture. The present invention adopts a four - lens structure. The combination of the surface shape structure and the optimized range of optical parameters of each lens can effectively shorten the overall size of the imaging lens and increase its lens viewing angle while maintaining high imaging quality, and has high resolution brought by high pixels. The present invention provides an optical imaging lens integrating a wide viewing angle and a large aperture, which can be used for small or thin portable devices that need to be equipped with high - imaging - quality equipment. Brief Description of the Drawings:

[0018] Figure 1 It is a schematic structural diagram of Embodiment 1 of the present invention;

[0019] Figure 2 It is the field curvature and distortion diagram of Embodiment 1 of the present invention;

[0020] Figure 3 It is a schematic structural diagram of Embodiment 2 of the present invention;

[0021] Figure 4 It is the field curvature and distortion diagram of Embodiment 2 of the present invention;

[0022] Figure 5 It is a schematic structural diagram of Embodiment 3 of the present invention;

[0023] Figure 6 It is the field curvature and distortion diagram of Embodiment 3 of the present invention;

[0024] Figure 7 It is a schematic structural diagram of Embodiment 4 of the present invention;

[0025] Figure 8 It is the field curvature and distortion diagram of Embodiment 4 of the present invention;

[0026] Figure 9 It is a schematic structural diagram of Embodiment 5 of the present invention;

[0027] Figure 10 It is the field curvature and distortion diagram of Embodiment 5 of the present invention;

[0028] Figure 11 It is a schematic structural diagram of Embodiment 6 of the present invention;

[0029] Figure 12 It is the field curvature and distortion diagram of Embodiment 6 of the present invention; Detailed implementation manner:

[0030] Embodiment 1

[0031] The present invention is an optical imaging lens for digital products. As shown in Figures 1 - 2 Shown, this is Embodiment 1 of the present invention patent.

[0032] As shown in Figure 1 Shown, the optical imaging lens sequentially includes: a first lens 1, a diaphragm 6, a second lens 2, a third lens 3, a fourth lens 4, and a filter 5 along its optical axis from the object side 7 to the image side 8 direction (from left to right).

[0033] The first lens 1 described above is a lens with negative refractive power, and both its object-side surface and image-side surface are aspherical surfaces. The object-side surface of the first lens 1 is concave near the optical axis, that is, its object-side surface adopts an anti-curved surface design, which can effectively converge off-axis light, making the angle of incidence on the photosensitive element more consistent with the preset angle of the chip, and can further correct the aberration of the off-axis field of view.

[0034] The second lens 2 described above is a lens with positive refractive power. Both its object-side surface and the image-side surface near the optical axis are convex, and the image-side surface near the optical axis is concave.

[0035] The third lens 3 described above is a lens with positive refractive power.

[0036] The fourth lens 4 described above is a lens with negative refractive power. Its object-side surface is convex near the optical axis, its image-side surface is concave near the optical axis, and there is at least one convex critical point at the off-axis of its image-side surface. As Figure 1 shown, there is a convex critical point at the off-axis of the image-side surface of the fourth lens 4.

[0037] The aperture stop 6 is located between the first lens 1 and the second lens, and is close to the side of the object-side surface of the second lens. The filter 5 is located between the fourth lens 4 and the image side 8.

[0038] The object-side surfaces and image-side surfaces of all the above lenses are aspherical surfaces, and the refractive indices of the first lens 1, the second lens 2, and the third lens 3 are less than 1.6. All lenses can be made of resin material ASP.

[0039] The lens should at least satisfy the following relationships:

[0040] (1) -2.9 < f1 / f < -3.5;

[0041] (2) 3.0 < (f2 + f3) / f < 4.0.

[0042] In order to further optimize the parameters of the optical imaging lens, the optical parameters of this first embodiment should also satisfy the following relationships.

[0043] (3) -2.0 < f4 / f < 0.0;

[0044] (4) 1.5 < f1 / f4 < 4.5.

[0045] (5) 6.5 < (f12 + f34) / f < 8.5;

[0046] (6) 2.0 < ET3 / CT3 < 3.0;

[0047] (7) 1.2 < ΣCT / f < 2.2;

[0048] (8) 0 < (CT3 + CT4) / f34 < 1.1;

[0049] (9) 0.1 < (CT2 + CT3) × T23 < 0.6;

[0050] (10) 0.0 ≤ (R21 + R22) / (R11 + R12) < 2.2;

[0051] (11) 0.9 < (R41 + R42) / f < 2.2;

[0052] (12) 2.0 < TL / ImgH < 2.4;

[0053] (13) 2.0 < TL / Fno × f < 2.8;

[0054] (14) 35 ≤ V3 - V4;

[0055] (15) The maximum half field of view angle HFOV of the camera lens group satisfies 49° < HFOV < 58°.

[0056] Among the above conditions, the representations of relevant parameters are as follows:

[0057] f: The focal length of the lens;

[0058] f1: The focal length of the first lens;

[0059] f2: The focal length of the second lens;

[0060] f3: The focal length of the third lens;

[0061] f4: The focal length of the fourth lens;

[0062] f12: The combined focal length of the first and second lenses;

[0063] f34: The combined focal length of the third and fourth lenses;

[0064] ET3: The edge thickness of the third lens;

[0065] CT3: The central thickness of the third lens on the optical axis;

[0066] CT4: The central thickness of the fourth lens on the optical axis;

[0067] ΣCT: The sum of the central thicknesses of all the lenses on the optical axis;

[0068] CT2: The central thickness of the second lens on the optical axis;

[0069] T23: The distance between the second lens and the third lens on the optical axis;

[0070] R21: The radius of curvature of the object side surface of the second lens;

[0071] R22: The radius of curvature of the image side surface of the second lens;

[0072] R11: The radius of curvature of the object side surface of the first lens;

[0073] R12: The radius of curvature of the image side surface of the first lens;

[0074] R41: The radius of curvature of the object side surface of the fourth lens;

[0075] R42: The radius of curvature of the image side surface of the fourth lens;

[0076] TL: The total optical length of the lens;

[0077] ImgH: Half of the diagonal length of the effective pixel area on the imaging surface of the lens;

[0078] Fno: The aperture value of the imaging optical lens;

[0079] V3: The Abbe number of the third lens;

[0080] V4: The Abbe number of the fourth lens;

[0081] HFOV: Half of the maximum field of view angle of the lens.

[0082] According to the conditions described above, the specific condition values adopted in the first embodiment are shown in the following table:

[0083] Table 1-1 shows the corresponding specification parameters of each component of the lens in the first embodiment from left to right for each surface.

[0084]

[0085]

[0086] Refer to Table 1-2 shown below, which is the aspheric coefficient of the first embodiment of the present invention.

[0087]

[0088]

[0089] According to the conditions described above, the specific condition parameters adopted in the first embodiment of the present invention are shown in Table 1-3 below.

[0090]

[0091] See Figure 2As shown, this is the field curvature and distortion diagram of the first embodiment of the present invention.

[0092] Embodiment 2

[0093] See Figure 3 、 Figure 4 As shown, this is the second embodiment of the present invention, which has the same structure as the first embodiment above, except that the parameters of the lens are slightly adjusted.

[0094] The following Table 2-1 shows the corresponding specification parameters of each component of the lens in this embodiment for each surface from left to right.

[0095]

[0096] Referring to Table 2-2 below, this is the aspherical coefficient of the second embodiment of the present invention.

[0097]

[0098]

[0099] According to the conditions described above, the specific condition parameters adopted in the second embodiment of the present invention are shown in Table 2-3 below.

[0100]

[0101]

[0102] See Figure 4 As shown, this is the field curvature and distortion diagram of this embodiment.

[0103] Embodiment 3

[0104] See Figure 5 、 Figure 6 As shown, this is the third embodiment of the present invention, which has the same structure as the first embodiment above, except that the parameters of the lens are slightly adjusted.

[0105] The following Table 3-1 shows the corresponding specification parameters of each component of the lens in this embodiment for each surface from left to right.

[0106]

[0107]

[0108] Referring to Table 3-2 below, this is the aspherical coefficient of the third embodiment of the present invention.

[0109]

[0110]

[0111] According to the conditions described above, the specific condition parameters adopted in the third embodiment of the present invention are shown in Table 3-3 below.

[0112]

[0113] See Figure 6 as shown, this is the field curvature and distortion diagram of the third embodiment.

[0114] Embodiment 4

[0115] See Figure 7 and Figure 8 as shown, this is Embodiment 4 of the present invention, whose structure is the same as that of Embodiment 1 above, only with slight adjustments in the lens parameters.

[0116] The following Table 4-1 shows the corresponding specification parameters of each component of the lens in this fourth embodiment according to each surface from left to right.

[0117]

[0118]

[0119] Refer to Table 4-2 below. This is the aspheric coefficient of the fourth embodiment of the present invention.

[0120]

[0121]

[0122] According to the conditions described above, the specific condition parameters adopted in the fourth embodiment of the present invention are shown in Table 4-3 below.

[0123]

[0124] See Figure 8 as shown, this is the field curvature and distortion diagram of the fourth embodiment.

[0125] Embodiment 5

[0126] See Figure 9 and Figure 10 as shown, this is Embodiment 5 of the present invention, whose structure is the same as that of Embodiment 1 above, only with slight adjustments in the lens parameters.

[0127] The following Table 5-1 shows the corresponding specification parameters of each component of the lens in this fifth embodiment according to each surface from left to right.

[0128]

[0129] Refer to Table 5-2 below. This is the aspheric coefficient of the fifth embodiment of the present invention.

[0130]

[0131]

[0132] According to the conditions described above, the specific condition parameters adopted in the fifth embodiment of the present invention are shown in Table 5-3 below.

[0133]

[0134]

[0135] See Figure 10 as shown, this is the field curvature and distortion diagram of the fifth embodiment.

[0136] Embodiment 6

[0137] See Figure 11 、 Figure 12 as shown, this is the sixth embodiment of the present invention, whose structure is the same as that of the first embodiment above, only with slight adjustments to the lens parameters.

[0138] The following Table 6-1 shows the corresponding specification parameters of each component of the lens in this embodiment according to the surfaces from left to right.

[0139]

[0140]

[0141] Refer to Table 6-2 below, which shows the aspheric coefficients of the sixth embodiment of the present invention.

[0142]

[0143]

[0144] According to the conditions described above, the specific condition parameters adopted in the sixth embodiment of the present invention are shown in Table 6-3 below.

[0145]

[0146] See Figure 12 as shown, this is the field curvature and distortion diagram of the sixth embodiment.

[0147] In summary, the present invention adopts a four-lens structure, and the combination of the surface shape structure and the optimization range of the optical parameters of each lens can effectively shorten the overall size of the imaging lens and increase its lens viewing angle while maintaining high imaging quality, and has high resolution brought by high pixels. The present invention provides an optical imaging lens integrating a wide viewing angle and a large aperture, which can be used for small or thin portable devices that require high imaging quality equipment.

[0148] Certainly, the above are only specific embodiments of the present invention patent and do not limit the scope of implementation of the present invention patent. Any equivalent changes or modifications made according to the structure, features and principles described in the patent scope of the present invention patent application shall be included within the patent scope of the present invention patent application.

Claims

1. An optical imaging lens, characterized in that: The lens sequentially includes, along its optical axis from the object side to the image side: A first lens with negative refractive power, having a concave surface at a position near the optical axis on its object side surface; A diaphragm located between the first lens and the second lens; A second lens with positive refractive power, having convex surfaces at positions near the optical axis on both its object side surface and image side surface; A third lens with positive refractive power; A fourth lens with negative refractive power, having a convex surface at a position near the optical axis on its object side surface, a concave surface at a position near the optical axis on its image side surface, and having at least one convex critical point at a position far from the optical axis on its image side surface; And a filter and an imaging surface, with the filter located between the fourth lens and the imaging surface; The object side surfaces and image side surfaces of all the above lenses are aspherical surfaces, and the refractive indices of the first lens, the second lens, and the third lens are less than 1.6; The lens satisfies the following relationships: (1) -2.9 < f1 / f < -3.5; (2) 3.0 < (f2 + f3) / f < 4.0; (3) -2.0 < f4 / f < 0.0; (4) 1.5 < f1 / f4 < 4.5; (5) 6.5 < (f12 + f34) / f < 8.5; (6) 2.0 < ET3 / CT3 < 3.0; (7) 1.2 < ΣCT / f < 2.2; (8) 0 < (CT3 + CT4) / f34 < 1.1; (9) 0.1 < (CT2 + CT3)×T23 < 0.6; (10) 0.0 ≤ (R21 + R22) / (R11 + R12) < 2.2; (11) 0.9 < (R41 + R42) / f < 2.2; (12) 2.0 < TL / ImgH < 2.4; (13) 2.0 < TL / Fno×f < 2.8; (14) 35 ≤ V3 - V4; Among the above conditions, the meanings of the relevant parameters are as follows: f: is the focal length of the lens; f1: is the focal length of the first lens; f2: is the focal length of the second lens; f3: is the focal length of the third lens; f4: is the focal length of the fourth lens; f12: is the combined focal length of the first lens and the second lens; f34: is the combined focal length of the third lens and the fourth lens; ET3: is the edge thickness of the third lens; CT3: is the central thickness of the third lens on the optical axis; ΣCT: is the total sum of the central thicknesses of all the lenses on the optical axis; CT2: is the central thickness of the second lens on the optical axis; CT3: is the central thickness of the third lens on the optical axis; CT4: is the central thickness of the fourth lens on the optical axis; R21: is the radius of curvature of the object side surface of the second lens; R22: is the radius of curvature of the image side surface of the second lens; R41: is the radius of curvature of the object side surface of the fourth lens; R42: is the radius of curvature of the image side surface of the fourth lens; TL: is the overall optical length of the lens; ImgH: is half of the diagonal length of the effective pixel area on the imaging surface of the lens; Fno: is the aperture value of the lens; V3: is the Abbe number of the third lens; V4: is the Abbe number of the fourth lens.

2. The optical imaging lens according to claim 1, wherein: The lens also satisfies the following conditions: (15) The maximum half field of view angle HFOV of the camera lens group satisfies 49° < HFOV < 58°; In the above conditions, the representations of relevant parameters are as follows: HFOV: Half of the maximum field of view angle of the said lens.

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