TWI719240B - Slim lens assembly - Google Patents

Abstract

A slim lens assembly includes a first lens, a second lens, a third lens and a fourth lens. The first lens is with positive refractive power and includes a convex surface facing an image side. The second lens is with positive refractive power and includes a concave surface facing the image side. The third lens is with positive refractive power and includes a concave surface facing the object side and a convex surface facing the image side. The fourth lens is with positive refractive power. The first lens, the second lens, the third lens and the fourth lens are arranged in order from the object side to the image side along an optical axis.

Description

Thin lens

The present invention relates to a thin lens.

The development trend of today's thin lens, in addition to the continuous development towards miniaturization and high resolution, with different application requirements, it also needs to have the ability to resist environmental temperature changes. The conventional thin lens can no longer meet today's needs. There is another thin lens with a new architecture that can simultaneously meet the needs of miniaturization, high resolution, and resistance to environmental temperature changes.

In view of this, the main purpose of the present invention is to provide a thin lens with short overall length, high resolution, resistance to environmental temperature changes, but still having good optical performance.

The thin lens of the present invention includes a first lens, a second lens, a third lens, and a fourth lens. The first lens has positive refractive power and includes a convex surface facing an image side. The second lens has positive refractive power and includes a concave surface facing the image side. The third lens has positive refractive power and includes a concave surface facing an object side and a convex surface facing the image side. The fourth lens has positive refractive power. The first lens, the second lens, the third lens and the fourth lens are arranged in order from the object side to the image side along an optical axis.

The thin lens of the present invention includes a first lens, a second lens, a third lens, an aperture, and a fourth lens. The first lens has positive refractive power and includes a convex surface facing an image side. The second lens has positive refractive power and includes a convex surface facing an object side and a concave surface facing the image side. The third lens has positive refractive power and includes a concave surface facing the object side and a convex surface facing the image side. The fourth lens has positive refractive power. The first lens, the second lens, the third lens, the aperture and the fourth lens are arranged in order from the object side to the image side along an optical axis.

The first lens may further include a convex surface facing the object side, and the thin lens satisfies the following condition: f ₂₃₄ >0; where f ₂₃₄ is an effective focal length of a combination of the second lens, the third lens, and the fourth lens.

The thin lens of the present invention may further include an aperture set between the third lens and the fourth lens.

The first lens may further include a convex surface facing the object side.

The fourth lens includes a convex surface facing the object side and a concave surface facing the image side.

The thin lens satisfies the following conditions: 0.3<SL/TTL<0.8; where SL is the distance between the aperture and an imaging surface on the optical axis, and TTL is one of the object side of the first lens to the imaging surface on the optical axis. spacing.

The thin lens satisfies the following conditions: 0<f ₂₃₄ /f ₄ <1; where f ₂₃₄ is the effective focal length of the combination of the second lens, the third lens and the fourth lens, and f ₄ is the effective focal length of the fourth lens .

The thin lens satisfies the following conditions: 0<(f ₁ +f ₃ )/(f ₂ +f ₄ )<10; where f ₁ is an effective focal length of the first lens, and f ₂ is an effective focal length of the second lens , F ₃ is an effective focal length of the third lens, and f ₄ is an effective focal length of the fourth lens.

The thin lens satisfies the following conditions: R ₁₂ /f ₁ <0; where R ₁₂ is a curvature radius of an image side surface of the _{first lens, and f 1} is an effective focal length of the first lens.

The thin lens satisfies the following conditions: 0<f ₂₃₄ <30; among which, f ₂₃₄ is the effective focal length of a combination of the second lens, the third lens and the fourth lens.

The thin lens satisfies the following conditions: 0.3<SL/TTL<0.65; where SL is the distance from the aperture to an imaging surface on the optical axis, and TTL is one of the object side of the first lens to one of the imaging surface on the optical axis spacing.

The thin lens satisfies the following conditions: -30<R ₁₂ /f ₁ <0; where R ₁₂ is a radius of curvature of an image side surface of the _{first lens, and f 1} is an effective focal length of the first lens.

In order to make the above-mentioned objects, features, and advantages of the present invention more obvious and understandable, preferred embodiments are described in detail below in conjunction with the accompanying drawings.

1, 2: Thin lens

L11, L21: the first lens

L12, L22: second lens

L13, L23: third lens

L14, L24: fourth lens

ST1, ST2: Aperture

OF1, OF2: filter

OA1, OA2: Optical axis

IMA1, IMA2: imaging surface

S11, S12, S13, S14, S15: surface

516, S17, S18, S19, S110: surface

S111: Noodles

S21, S22, S23, S24, S25: surface

S26, S27, S28, S29, S210: surface

S211: Noodles

FIG. 1 is a schematic diagram of the lens arrangement of the first embodiment of the thin lens according to the present invention.

FIG. 2A is a field curve diagram of the first embodiment of the thin lens according to the present invention.

FIG. 2B is a distortion diagram of the first embodiment of the thin lens according to the present invention.

Figure 2C is a Modulation Transfer Function diagram of the first embodiment of the thin lens according to the present invention.

FIG. 3 is a schematic diagram of the lens configuration of the second embodiment of the thin lens according to the present invention.

FIG. 4A is a field curve diagram of the second embodiment of the thin lens according to the present invention.

FIG. 4B is a distortion diagram of the second embodiment of the thin lens according to the present invention.

Figure 4C is a Modulation Transfer Function diagram of the second embodiment of the thin lens according to the present invention.

Please refer to FIG. 1, which is a schematic diagram of the lens configuration of the first embodiment of the thin lens according to the present invention. The thin lens 1 includes a first lens L11, a second lens L12, a third lens L13, an aperture ST1, a fourth lens L14, and a filter in order from an object side to an image side along an optical axis OA1. Light film OF1. When imaging, the light from the object side is finally imaged on an imaging surface IMA1.

The first lens L11 is a biconvex lens with positive refractive power and is made of glass material. The object side surface S11 is a convex surface, the image side surface S12 is a convex surface, and both the object side surface S11 and the image side surface S12 are spherical surfaces.

The second lens L12 is a meniscus lens with positive refractive power and is made of glass. The object side surface S13 is a convex surface, the image side surface S14 is a concave surface, and both the object side surface S13 and the image side surface S14 are spherical surfaces.

The third lens L13 is a meniscus lens with positive refractive power and is made of glass. The object side surface S15 is concave, the image side surface S16 is convex, and both the object side surface S15 and the image side surface S16 are spherical surfaces.

The fourth lens L14 is a meniscus lens with positive refractive power and is made of glass. The object side surface S18 is convex, the image side surface S19 is concave, and both the object side surface S18 and the image side surface S19 are spherical surfaces.

The object side surface S110 and the image side surface S111 of the filter OF1 are both flat surfaces.

In addition, the thin lens 1 in the first embodiment satisfies at least one of the following conditions: 0<(f1 ₁ +f1 ₃ )/(f1 ₂ +f1 ₄ )<10 (1)

f1 ₂₃₄ >0 (2)

0<f1 ₂₃₄ <30 (3)

0<f1 ₂₃₄ /f1 ₄ <1 (4)

0.3<SL1/TTL1<0.8 (5)

0.3<SL1/TTL1<0.65 (6)

R1 ₁₂ /f1 ₁ <0 (7)

-30<R1 ₁₂ /f1 ₁ <0 (8)

Wherein, f1 ₁ is one of the effective focal length of the first lens L11, f1 ₂ is one of the effective focal length of the second lens L12, f1 ₃ is one of the effective focal length of the third lens L13, f1 ₄ is one of the effective focal length of the fourth lens L14, f1 ₂₃₄ is the effective focal length of the combination of the second lens L12, the third lens L13 and the fourth lens L14, SL1 is the distance between the aperture ST1 and the imaging surface IMA1 on the optical axis OA1, and TTL1 is the object side of the first lens L11 A distance between S11 and the imaging surface IMA1 on the optical axis OA1, R1 ₁₂ is a radius of curvature of the image side surface S12 of the first lens L11.

Utilizing the above-mentioned lens, aperture ST1, and a design satisfying at least one of conditions (1) to (8), the thin lens 1 can effectively shorten the total length of the lens, correct aberrations, improve resolution, and resist environmental temperature changes.

Table 1 is a table of relevant parameters of each lens of the thin lens 1 in Figure 1. The data in Table 1 shows that the effective focal length of the thin lens 1 of the first embodiment is 9.021 mm, the aperture value is equal to 5.6, and the total lens length is equal to 13.7974 mm, The field of view is equal to 29 degrees.

Table 2 shows the values of the parameters in Condition (1) to Condition (8) and the calculated values of Condition (1) to Condition (8). It can be seen from Table 2 that the thin lens 1 of the first embodiment can all satisfy the condition (1) To the requirements of condition (8).

In addition, the optical performance of the thin lens 1 of the first embodiment can also meet the requirements, which can be seen from Figures 2A to 2C. FIG. 2A shows the field curvature of the thin lens 1 of the first embodiment. Figure 2B shows a distortion (Distortion) diagram of the thin lens 1 of the first embodiment. Figure 2C shows a Modulation Transfer Function diagram of the thin lens 1 of the first embodiment.

It can be seen from Figure 2A that the thin lens 1 of the first embodiment has a field curvature of -0.01 for light with wavelengths of 0.810μm, 0.830μm, and 0.850μm in the Tangential and Sagittal directions. mm to 0.045mm.

It can be seen from Figure 2B (the three lines in the figure are almost overlapped, so that there is only one line), it can be seen that the thin lens 1 of the first embodiment produces light with wavelengths of 0.810μm, 0.830μm, and 0.850μm. The distortion is between -0.7% and 0%.

It can be seen from Figure 2C that the thin lens 1 of the first embodiment has a field of view height of 1.3608 for light with a wavelength range of 0.810μm to 0.850μm in the Tangential direction and the Sagittal direction respectively. mm, 1.8144mm, 2.2680mm, 2.4000mm, the spatial frequency is between 0lp/mm and 200lp/mm, and the value of the modulation transfer function is between 0.0 and 1.0.

It is obvious that the field curvature and distortion of the thin 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 the lens configuration of the second embodiment of the thin lens according to the present invention. The thin lens 2 includes a first lens L21, a second lens L22, a third lens L23, an aperture ST2, a fourth lens L24, and a filter in order from an object side to an image side along an optical axis OA2. Light film OF2. When imaging, the light from the object side is finally imaged on an imaging surface IMA2.

The first lens L21 is a double-convex lens with positive refractive power and is made of plastic material. The object side surface S21 is a convex surface, the image side surface S22 is a convex surface, and both the object side surface S21 and the image side surface S22 are aspherical surfaces.

The second lens L22 is a meniscus lens with positive refractive power and is made of plastic material. The object side surface S23 is a convex surface, the image side surface S24 is a concave surface, and both the object side surface S23 and the image side surface S24 are aspherical surfaces.

The third lens L23 is a meniscus lens with positive refractive power and is made of glass. The object side surface S25 is a concave surface, the image side surface S26 is a convex surface, and both the object side surface S25 and the image side surface S26 are spherical surfaces.

The fourth lens L24 is a meniscus lens with positive refractive power and is made of plastic material. The object side surface S28 is convex, the image side surface S29 is concave, and both the object side surface S28 and the image side surface S29 are aspherical surfaces.

The object side surface S210 and the image side surface S211 of the filter OF2 are both flat surfaces.

In addition, the thin lens 2 in the second embodiment satisfies at least one of the following conditions: 0<(f2 ₁ +f2 ₃ )/(f2 ₂ +f2 ₄ )<10 (9)

f2 ₂₃₄ >0 (10)

0<f2 ₂₃₄ <30 (11)

0<f2 ₂₃₄ /f2 ₄ <1 (12)

0.3<SL2/TTL2<0.8 (13)

0.3<SL2/TTL2<0.65 (14)

R2 ₁₂ /f2 ₁ <0 (15)

-30<R2 ₁₂ /f2 ₁ <0 (16)

The _{definitions of f2 1} , f2 ₂ , f2 ₃ , f2 ₄ , f2 ₂₃₄ , SL2, TTL2 and R2 _{12 described} above are the same as those of f1 ₁ , f1 ₂ , f1 ₃ , f1 ₄ , f1 ₂₃₄ , SL1, TTL1 and R1 in the first embodiment _{The definition of 12 is} the same, so I won't repeat it here.

Using the above-mentioned lens, aperture ST2, and a design that satisfies at least one of conditions (9) to (16), the thin lens 2 can effectively shorten the total length of the lens, correct aberrations, improve resolution, and resist environmental temperature changes.

Table 3 is a table of relevant parameters of each lens of the thin lens 2 in Figure 3. The data in Table 3 shows that the effective focal length of the thin lens 2 of the second embodiment is equal to 9.673mm, the aperture value is equal to 3.6, and the total lens length is equal to 13.7974mm, The field of view is equal to 27 degrees.

The concavity z of the aspheric surface 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

Among them: c: curvature; h: the vertical distance from any point on the lens surface to the optical axis; k: conic coefficient; A~D: aspherical coefficient.

Table 4 is a table of related parameters of the aspheric surface of each lens in Table 3, where k is the Conic Constant, and A~D are the aspheric coefficients.

Table 5 shows the values of the parameters in Condition (9) to Condition (18) and the calculated values from Condition (9) to Condition (18). It can be seen from Table 5 that the thin lens 2 of the second embodiment can all meet the condition (9) To the requirements of Condition (18).

In addition, the optical performance of the thin lens 2 of the second embodiment can also meet the requirements, which can be seen from Figures 4A to 4C. Fig. 4A shows the field curvature of the thin lens 2 of the second embodiment. FIG. 4B shows a distortion (Distortion) diagram of the thin lens 2 of the second embodiment. Figure 4C shows a Modulation Transfer Function diagram of the thin lens 2 of the second embodiment.

It can be seen from Figure 4A that the thin lens 2 of the second embodiment has a field curvature of -0.02 in the Tangential and Sagittal directions for light with wavelengths of 0.810μm, 0.830μm, and 0.850μm. mm to 0.08mm.

It can be seen from Fig. 4B (the three lines in the figure are almost overlapped, so that there is only one line), it can be seen that the thin lens 2 of the second embodiment produces light with wavelengths of 0.810μm, 0.830μm, and 0.850μm. The distortion is between 0% and 0.5%.

It can be seen from Figure 4C that the thin lens 2 of the second embodiment has a field of view height of 1.3608 for light with a wavelength range of 0.810μm to 0.850μm in the Tangential direction and the Sagittal direction respectively. mm, 1.8144mm, 2.2680mm, 2.4000mm, the spatial frequency is between 0lp/mm and 200lp/mm, and the value of the modulation transfer function is between 0.03 and 1.0.

It is obvious that the field curvature and distortion of the thin lens 2 of the second embodiment can be effectively corrected, and the lens resolution can also meet the requirements, thereby obtaining better optical performance.

In the above embodiments, the third lens is made of glass material. However, it can be understood that if the third lens is made of plastic material, it should also belong to the scope of the present invention.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention. Anyone familiar with the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection of the present invention The scope shall be subject to those defined by the attached patent scope.

1‧‧‧Thin lens

L11‧‧‧First lens

L12‧‧‧Second lens

L13‧‧‧Third lens

L14‧‧‧Fourth lens

ST1‧‧‧Aperture

OF1‧‧‧Filter

OA1‧‧‧Optical axis

IMA1‧‧‧imaging surface

S11, S12, S13, S14, S15‧‧‧surface

S16, S17, S18, S19, S110‧‧‧face

S111‧‧‧Noodles

Claims (10)

A thin lens mainly composed of a first lens, a second lens, a third lens, an aperture, and a fourth lens; the first lens has a positive refractive power, and the first lens includes a convex surface facing an image side; The second lens has a positive refractive power, the second lens includes a concave surface facing the image side; the third lens has a positive refractive power, the third lens includes a concave surface facing an object side and a convex surface facing the image side; the fourth lens The lens has positive refractive power; wherein the first lens, the second lens, the third lens, and the fourth lens are arranged in order from the object side to the image side along an optical axis; wherein the thin lens satisfies the following conditions: 0.3<SL/TTL<0.8; where SL is a distance from the aperture to an imaging surface on the optical axis, and TTL is a distance from an object side of the first lens to the imaging surface on the optical axis. A thin lens mainly composed of a first lens, a second lens, a third lens, an aperture, and a fourth lens; the first lens has a positive refractive power, and the first lens includes a convex surface facing an image side; The second lens has positive refractive power, the second lens includes a convex surface facing an object side and a concave surface facing the image side; the third lens has positive refractive power, the third lens includes a concave surface facing the object side and a convex surface facing The image side; the fourth lens has a positive refractive power; The first lens, the second lens, the third lens, the aperture, and the fourth lens are arranged in order from the object side to the image side along an optical axis. A thin lens mainly composed of a first lens, a second lens, a third lens, an aperture, and a fourth lens; the first lens has a positive refractive power, and the first lens includes a convex surface facing an image side; The second lens has a positive refractive power, the second lens includes a concave surface facing the image side; the third lens has a positive refractive power, the third lens includes a concave surface facing an object side and a convex surface facing the image side; the fourth lens The lens has a positive refractive power; wherein the first lens, the second lens, the third lens, the aperture, and the fourth lens are arranged in order from the object side to the image side along an optical axis. As described in item 2 of the patent application, the first lens further includes a convex surface facing the object side, and the thin lens satisfies the following condition: f ₂₃₄ >0; where f _{234 is} the second lens, the An effective focal length of a combination of the third lens and the fourth lens. The thin lens described in claim 1, wherein the aperture is arranged between the third lens and the fourth lens, and the first lens further includes a convex surface facing the object side. The thin lens described in any one of claims 1 to 5 of the scope of patent application, wherein the fourth lens includes a convex surface facing the object side. For the thin lens described in any one of claims 2 to 3 in the scope of the patent application, the thin lens satisfies the following conditions: 0.3<SL/TTL<0.8; where SL is a distance from the aperture to an imaging surface on the optical axis, and TTL is a distance from an object side of the first lens to the imaging surface on the optical axis. For the thin lens described in any one of claims 1 to 5 in the scope of the patent application, the thin lens satisfies the following conditions: 0<f ₂₃₄ /f ₄ <1; where f _{234 is} the second lens, An effective focal length of the combination of the third lens and the fourth lens, f _{4 is} an effective focal length of the fourth lens. Such as the thin lens described in any one of claims 1 to 5 of the scope of patent application, wherein the thin lens satisfies the following conditions: 0<(f ₁ +f ₃ )/(f ₂ +f ₄ )<10; Wherein, f _{1 is} an effective focal length of the first lens, f _{2 is} an effective focal length of the second lens, f _{3 is} an effective focal length of the third lens, and f _{4 is} an effective focal length of the fourth lens. The thin lens described in any one of claims 1 to 5 in the scope of the patent application, wherein the thin lens satisfies the following conditions: R ₁₂ /f ₁ <0; where R _{12 is an image of} the first lens A radius of curvature of the side surface, f _{1 is} an effective focal length of the first lens.

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