TW201626028A - Lens assembly - Google Patents

Abstract

A lens assembly includes a first lens, a second lens and a third lens, all of which are arranged in sequence from an object side to an image side along an optical axis. The first lens is a biconvex lens with positive refractive power. The third lens is with positive refractive power. The first lens and the second lens are cemented together to form a cemented lens. The cemented lens is with positive refractive power. The first and second lenses satisfy the condition of 1.2965 ≤ f12/f ≤ 1.3368, wherein f12 is an effective focal length of a combination of the first lens and the second lens, and f is an effective length of the lens assembly.

Description

Imaging lens

The present invention relates to an imaging lens.

In order to achieve miniaturization and weight reduction, the lens used in the lens of the mobile phone is made of a plastic material. However, the lens using the all-plastic lens has a large temperature effect, and the image quality is easily affected by the ambient temperature. Conventional imaging lenses are no longer able to meet today's needs, and there is a need for another new architecture imaging lens to meet the needs of miniaturization, lightweight, and low temperature effects.

In view of this, the main object of the present invention is to provide an imaging lens which has a short total lens length and a low temperature effect, but still has good optical performance, and the lens resolution can also meet the requirements.

The imaging lens of the present invention sequentially includes a first lens, a second lens and a third lens from the object side to the image side along the optical axis. The first lens is a lenticular lens having a positive refractive power. The second lens has a negative refractive power. The third lens has a positive refractive power. The first lens and the second lens glue form a cemented lens, and the cemented lens has a positive refractive power.

The second lens is a biconcave lens.

The third lens is a convex-concave lens, and the convex surface of the third lens faces the object side concave surface toward the image side.

The first lens and the second lens satisfy the following conditions: 1.2965 f ₁₂ /f 1.3368; wherein f ₁₂ is a combined effective focal length of the first lens and the second lens, and f is an effective focal length of the imaging lens.

The first lens and the second lens satisfy the following conditions: 1.0308 f ₁₂ /TTL 1.0459; wherein f ₁₂ is a combined effective focal length of the first lens and the second lens, and TTL is a distance from the object side of the first lens to the imaging surface on the optical axis.

The first lens satisfies the following conditions: 0.5844 f ₁ /f 0.6067; wherein f ₁ is the effective focal length of the first lens, and f is the effective focal length of the imaging lens.

Wherein the second lens satisfies the following condition: -0.7226 f ₂ /f -0.7052; wherein f ₂ is the effective focal length of the second lens, and f is the effective focal length of the imaging lens.

The third lens satisfies the following conditions: 4.1071 f ₃ /f 5.1124; wherein f ₃ is the effective focal length of the third lens, and f is the effective focal length of the imaging lens.

The imaging lens satisfies the following conditions: 0.7824 f/TTL 0.7945; wherein f is the effective focal length of the imaging lens, and TTL is the distance from the object side of the first lens to the imaging plane on the optical axis.

The first lens and the second lens are made of glass material, and the third lens is made of plastic material.

At least one of the object side surface and the image side surface of the first lens is an aspherical surface, and at least one of the object side surface and the image side surface of the second lens is an aspherical surface, and both the object side surface and the image side surface of the third lens are aspherical surfaces.

The imaging lens of the present invention may further include an aperture disposed between the object side and the first lens.

The above described objects, features, and advantages of the invention will be apparent from the description and appended claims

1, 2‧‧‧ imaging lens

L1G, L2G‧‧‧ cemented lens

L11, L21‧‧‧ first lens

L12, L22‧‧‧ second lens

L13, L23‧‧‧ third lens

ST1, ST2‧‧ ‧ aperture

OF1, OF2‧‧‧ Filters

OA1, OA2‧‧‧ optical axis

IMA1, IMA2‧‧‧ imaging surface

S11, S12, S13, S14, S15‧‧

S16, S17, S18, S19‧‧‧

S21, S22, S23, S24, S25‧‧‧

S26, S27, S28, S29‧‧‧

1 is a schematic view showing a lens configuration and an optical path of a first embodiment of an imaging lens according to the present invention.

Fig. 2A is a longitudinal aberration diagram of the imaging lens of Fig. 1.

Fig. 2B is a field curvature diagram of the imaging lens of Fig. 1.

Fig. 2C is a distortion diagram of the imaging lens of Fig. 1.

Fig. 2D is a lateral chromatic aberration diagram of the imaging lens of Fig. 1.

Fig. 3 is a schematic view showing a lens configuration and an optical path of a second embodiment of the imaging lens according to the present invention.

Fig. 4A is a longitudinal aberration diagram of the imaging lens of Fig. 3.

Fig. 4B is a field curvature diagram of the imaging lens of Fig. 3.

Fig. 4C is a distortion diagram of the imaging lens of Fig. 3.

Fig. 4D is a lateral chromatic aberration diagram of the imaging lens of Fig. 3.

Please refer to FIG. 1. FIG. 1 is a schematic view showing a lens configuration and an optical path of a first embodiment of an imaging lens according to the present invention. The imaging lens 1 sequentially includes an aperture ST1, a first lens L11, a second lens L12, a third lens L13, and a filter OF1 along the optical axis OA1 from the object side to the image side. At the time of imaging, the light from the object side is finally imaged on an image plane IMA1. The first lens L11 is a lenticular lens having a positive refractive power made of a glass material, the object side surface S12 being an aspherical surface, and the image side surface S13 being a spherical surface. The second lens L12 is a biconcave lens having a negative refractive power made of a glass material, the object side surface S14 being a spherical surface, and the image side surface S15 being an aspherical surface. The first lens L11 and the second lens L12 are glued into a cemented lens L1G, and the cemented lens L1G has a positive refractive power. The third lens L13 is a convex-concave lens having a positive refractive power made of a plastic material, and the object thereof The side surface S16 is a convex surface, the image side surface S17 is a concave surface, and the object side surface S16 and the image side surface S17 are both aspherical surfaces. The filter OF1 has a flat surface S18 and an image side surface S19.

In addition, in order to maintain good optical performance of the imaging lens of the present invention, the imaging lens 1 of the first embodiment is required to satisfy the following six conditions:

Wherein f1 ₁₂ is the combined effective focal length of the first lens L11 and the second lens L12, f1 is the effective focal length of the imaging lens 1, and TTL1 is the distance from the object side S12 of the first lens L11 to the imaging plane IMA1 on the optical axis OA1. F1 ₁ is the effective focal length of the first lens L11, f1 ₂ is the effective focal length of the second lens L12, and f1 ₃ is the effective focal length of the third lens L13.

By using the above lens and aperture ST1 design, the imaging lens 1 can effectively shorten the total length of the lens, effectively correct aberrations, improve lens resolution, and reduce the influence of ambient temperature on imaging quality.

Table 1 is a table of related parameters of the lenses of the imaging lens 1 in Fig. 1. Table 1 shows that the effective focal length of the imaging lens 1 of the first embodiment is equal to 1.116 mm, the aperture value is equal to 2.8, and the viewing angle is equal to 61.0 degrees.

The aspherical surface depression z of each lens in Table 1 is obtained by the following formula: z = ch ² /{1 + [1 - (k + 1) c ² h ² ] ^1/2 } + Ah ⁴ + Bh ⁶ + Ch ⁸ +Dh ¹⁰ +Eh ¹²

Where: c: curvature; h: vertical distance from any point on the lens surface to the optical axis; k: conic coefficient; A~E: aspheric coefficient.

Table 2 is a table of related parameters of the aspherical surface of each lens in Table 1, where k is a conical coefficient (Conic Constant) and A~E is an aspherical coefficient.

In the imaging lens 1 of the first embodiment, the combined effective focal length f1 ₁₂ = 1.447 mm of the first lens L11 and the second lens L12, the effective focal length f1 of the imaging lens 1 is 1.116 mm, and the object side S12 of the first lens L11 to the imaging surface The distance IMA1 is on the optical axis OA1 is TTL1=1.404 mm, the effective focal length f1 _{1 of the} first lens L11 is 0.925 mm, the effective focal length of the second lens L12 is f1 ₂ = -0.778 mm, and the effective focal length of the third lens L13 is f1 ₃ = 5.705mm. Information obtained by the _{f1 12 /f1=1.2965,f1 12 /TTL1=1.0308,f1 1 /f1=0.5844,f1 2} /f1=-0.7052,f1 3 /f1=5.1124,f1/TTL1=0.7945, meet Jieneng Requirements for the above conditions (1) to (6).

In addition, the optical performance of the imaging lens 1 of the first embodiment can also be achieved, which can be seen from the 2A to 2D drawings. Fig. 2A is a longitudinal aberration diagram of the imaging lens 1 of the first embodiment. 2B is a Field Curvature diagram of the imaging lens 1 of the first embodiment. Fig. 2C is a distortion diagram of the imaging lens 1 of the first embodiment. 2D is a lateral color difference diagram of the imaging lens 1 of the first embodiment.

As can be seen from Fig. 2A, the longitudinal aberration of the imaging lens 1 of the first embodiment for light having a wavelength of 0.470 μm, 0.555 μm, and 0.650 μm is between -0.0105 mm and 0.009 mm. As can be seen from FIG. 2B, the imaging lens 1 of the first embodiment has a wavelength of 0.470. The light of μm, 0.555 μm, and 0.650 μm has a field curvature in the direction of the Tangential and the Sagittal direction between -0.06 mm and 0.00 mm. As can be seen from FIG. 2C, the imaging lens 1 of the first embodiment has a distortion of between 0.0% and 1.0% for light having a wavelength of 0.470 μm, 0.555 μm, and 0.650 μm. As can be seen from FIG. 2D, the imaging lens 1 of the first embodiment produces a lateral color difference of -1.0 μm to 0.75 μm for different wavelengths of the light having a wavelength of 0.470 μm, 0.555 μm, and 0.650 μm. between. It can be seen that the longitudinal aberration, field curvature, distortion, and lateral chromatic aberration of the imaging lens 1 of the first embodiment can be effectively corrected, and the lens resolution can also meet the requirements, thereby obtaining better optical performance.

Please refer to FIG. 3, which is a schematic diagram of a lens configuration and an optical path of a second embodiment of an imaging lens according to the present invention. The imaging lens 2 sequentially includes an aperture ST2, a first lens L21, a second lens L22, a third lens L23, and a filter OF2 from the object side to the image side along the optical axis OA2. At the time of imaging, the light from the object side is finally imaged on an image plane IMA2. The first lens L21 is a lenticular lens having a positive refractive power made of a glass material, the object side surface S22 being an aspherical surface, and the image side surface S23 being a spherical surface. The second lens L22 is a biconcave lens having a negative refractive power made of a glass material, the object side surface S24 being a spherical surface, and the image side surface S25 being an aspherical surface. The first lens L21 and the second lens L22 are glued into a cemented lens L2G, and the cemented lens L2G has a positive refractive power. The third lens L23 is a convex-concave lens having a positive refractive power made of a plastic material, the object side surface S26 being a convex surface, the image side surface S27 being a concave surface, and the object side surface S26 and the image side surface S27 being aspherical surfaces. The filter OF2 has a flat surface S28 and an image side surface S29.

In addition, in order to maintain good optical performance of the imaging lens of the present invention, the imaging lens 2 of the second embodiment is required to satisfy the following six conditions:

Wherein f2 ₁₂ is the combined effective focal length of the first lens L21 and the second lens L22, f2 is the effective focal length of the imaging lens 2, and TTL2 is the distance from the object side S22 of the first lens L21 to the imaging plane IMA2 on the optical axis OA2. F2 ₁ is the effective focal length of the first lens L21, f2 ₂ is the effective focal length of the second lens L22, and f2 ₃ is the effective focal length of the third lens L23.

By using the above lens and aperture ST2 design, the imaging lens 2 can effectively shorten the total length of the lens, effectively correct aberrations, improve lens resolution, and reduce the influence of ambient temperature on imaging quality.

Table 3 is a table of related parameters of the lenses of the imaging lens 2 in Fig. 3. Table 3 shows that the effective focal length of the imaging lens 2 of the second embodiment is equal to 1.117 mm, the aperture value is equal to 2.4, and the viewing angle is equal to 61.0 degrees.

The aspherical surface depression z of each lens in Table 3 is obtained by the following formula: z = ch ² /{1 + [1 - (k + 1) c ² h ² ] ^1/2 } + Ah ⁴ + Bh ⁶ + Ch ⁸ +Dh ¹⁰ +Eh ¹²

Where: c: curvature; h: vertical distance from any point on the lens surface to the optical axis; k: conic coefficient; A~E: aspheric coefficient.

Table 4 is a table of related parameters of the aspherical surface of each lens in Table 3, where k is a conical coefficient (Conic Constant) and A~E is an aspherical coefficient.

The imaging lens 2 of the second embodiment has a combination of the first lens L21 and the second lens L22 having an effective focal length f2 ₁₂ = 1.493 mm, an effective focal length f2 of the imaging lens 2 = 1.117 mm, and an object side S22 of the first lens L21 to the imaging surface. The distance IMA2 is on the optical axis OA2 is TTL2=1.427 mm, the effective focal length of the first lens L21 is f2 ₁ = 0.778 mm, the effective focal length of the second lens L22 is f2 ₂ = -0.077 mm, and the effective focal length of the third lens L23 is f2 ₃ = 4.588mm. Information obtained by the _{f2 12 /f2=1.3368,f2 12 /TTL2=1.0459,f2 1 /f2=0.6067,f2 2} /f2=-0.7226,f2 3 /f2=4.1071,f2/TTL2=0.7824, meet Jieneng Requirements for the above conditions (7) to (12).

In addition, the optical performance of the imaging lens 2 of the second embodiment can also be achieved, which can be seen from the 4A to 4D drawings. Fig. 4A is a longitudinal aberration diagram of the imaging lens 2 of the second embodiment. Fig. 4B is a field curvature diagram of the imaging lens 2 of the second embodiment. Fig. 4C is a distortion diagram of the imaging lens 2 of the second embodiment. Fig. 4D is a lateral chromatic aberration diagram of the imaging lens 2 of the second embodiment.

As can be seen from Fig. 4A, the longitudinal aberration of the imaging lens 2 of the second embodiment for light having a wavelength of 0.470 μm, 0.555 μm, and 0.650 μm is between -0.0135 mm and 0.009 mm. As can be seen from FIG. 4B, the imaging lens 2 of the second embodiment has a field curvature of -0.78 in the direction of the tangential direction and the sagittal direction for the light having a wavelength of 0.470 μm, 0.555 μm, and 0.650 μm. Between mm and 0.00 mm. As can be seen from Fig. 4C, the imaging lens 2 of the second embodiment has a distortion of between 0.0% and 1.2% for light having a wavelength of 0.470 μm, 0.555 μm, and 0.650 μm. As can be seen from FIG. 4D, the imaging lens 2 of the second embodiment has a lateral color difference of -1.0 μm to 0.75 μm for different wavelengths of the light having a wavelength of 0.470 μm, 0.555 μm, and 0.650 μm. between. It can be seen that the longitudinal aberration, curvature of field, distortion, and lateral chromatic aberration of the imaging lens 2 of the second embodiment can be effectively corrected, and the lens resolution can also be full. The requirements are sufficient to obtain better optical properties.

Although the present invention has been disclosed in the above preferred embodiments, it is not intended to limit the present invention, and it is possible to make some modifications without departing from the spirit and scope of the invention. And the scope of the present invention is defined by the scope of the appended claims.

1‧‧‧ imaging lens

L1G‧‧‧ cemented lens

L11‧‧‧ first lens

L12‧‧‧ second lens

L13‧‧‧ third lens

ST1‧‧‧ aperture

OF1‧‧‧Filter

OA1‧‧‧ optical axis

IMA1‧‧‧ imaging surface

S11, S12, S13, S14, S15‧‧

S16, S17, S18, S19‧‧‧

Claims (11)

An imaging lens sequentially includes, from the object side to the image side along the optical axis, a first lens having a positive refractive power and a second lens having a negative refractive power; the second lens having a negative refractive power; And a third lens having a positive refractive power; wherein the first lens and the second lens are combined to form a cemented lens, the cemented lens having a positive refractive power; wherein the first lens and the second lens satisfy the following conditions :1.2965 f ₁₂ /f 1.3368, wherein f ₁₂ is a combined effective focal length of the first lens and the second lens, and f is an effective focal length of the imaging lens. The imaging lens of claim 1, wherein the second lens is a biconcave lens. The imaging lens of claim 1, wherein the third lens is a convex-concave lens, and a convex surface of the third lens faces the object side concave surface toward the image side. The imaging lens of claim 1, wherein the first lens and the second lens satisfy the following condition: 1.0308 f ₁₂ /TTL 1.0459, wherein f ₁₂ is a combined effective focal length of the first lens and the second lens, and TTL is a distance from an object side of the first lens to an imaging surface on the optical axis. The imaging lens of claim 1, wherein the first lens satisfies the following condition: 0.5844 f ₁ /f 0.6067 wherein f _{1 is} the effective focal length of the first lens, and f is the effective focal length of the imaging lens. The imaging lens of claim 1, wherein the second lens satisfies the following condition: -0.7226 f ₂ /f -0.7052, where f _{2 is} the effective focal length of the second lens, and f is the effective focal length of the imaging lens. The imaging lens of claim 1, wherein the third lens satisfies the following condition: 4.1071 f ₃ /f 5.1124 wherein f _{3 is} the effective focal length of the third lens, and f is the effective focal length of the imaging lens. The imaging lens of claim 1, wherein the imaging lens satisfies the following condition: 0.7824 f/TTL 0.7945, where f is the effective focal length of the imaging lens, and TTL is the distance from the object side of the first lens to an imaging surface on the optical axis. The imaging lens of claim 1, wherein the first lens and the second lens are made of a glass material, and the third lens is made of a plastic material. The imaging lens of claim 1, wherein at least one side of the object side and the image side of the first lens is an aspherical surface, and at least one side of the object side and the image side of the second lens is an aspherical surface. Both the object side surface and the image side surface of the third lens are aspherical surfaces. The imaging lens of claim 1, further comprising an aperture disposed between the object side and the first lens.