TW201913166A - Thin lens - 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 invention relates to a thin lens.

The development trend of today's thin lenses, in addition to continuous miniaturization and high resolution development, with different application needs, also need to have the ability to resist environmental temperature changes, the conventional thin lenses can no longer meet today's needs, needs There is another thin lens with a new architecture to 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 a short overall lens length, high resolution, and 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 the 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 sequentially arranged along the optical axis from the object side to the image side.

The first lens may further include a convex surface facing the object side, wherein 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 disposed 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 plane on the optical axis, and TTL is the object side of the first lens to one of the imaging plane on the optical axis spacing.

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

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

The thin lens satisfies the following condition: R ₁₂ /f ₁ <0; wherein, R ₁₂ is a radius of curvature of one image side of one of the first lenses, and f ₁ is an effective focal length of one of the first lenses.

The thin lens satisfies the following conditions: 0<f ₂₃₄ <30; 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 meets the following conditions: 0.3<SL/TTL<0.65; where SL is the distance between the aperture and an imaging plane on the optical axis, and TTL is the object side of the first lens to one of the imaging plane on the optical axis spacing.

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

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

1, 2‧‧‧ thin lens

L11, L21‧‧‧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

S16, S17, S18, S19, S110

S111‧‧‧ noodles

S21, S22, S23, S24, S25

S26, S27, S28, S29, S210

S211‧‧‧ noodles

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

FIG. 2A is a field curvature 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.

FIG. 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 curvature 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.

FIG. 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 a lens configuration of a first embodiment of a 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 Optical sheet 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 made of glass material, its object side S11 is convex, the image side S12 is convex, and both the object side S11 and the image side S12 are spherical surfaces.

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

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

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

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

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)

Where f1 ₁ is one of the effective focal lengths of the first lens L11, f1 ₂ is one of the effective focal lengths of the second lens L12, f1 ₃ is one of the effective focal lengths of the third lens L13, and f1 ₄ is one of the effective focal lengths of the fourth lens L14, f1 ₂₃₄ is one of the effective focal lengths 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 plane IMA1 on the optical axis OA1, and TTL1 is the object side of the first lens L11 A distance from S11 to the imaging plane IMA1 on the optical axis OA1, R1 ₁₂ is a radius of curvature of the image side S12 of the first lens L11.

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

Table 1 is a table of related parameters of each lens of the thin lens 1 in FIG. 1, the data of the table 1 shows that the effective focal length of the thin lens 1 of the first embodiment is equal to 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 is the parameter values in Condition (1) to Condition (8) and the calculated values of Condition (1) to Condition (8). As can be seen from Table 2, the thin lens 1 of the first embodiment can 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, as can be seen from FIGS. 2A to 2C. Shown in FIG. 2A is a field curvature diagram of the thin lens 1 of the first embodiment. FIG. 2B is a distortion diagram of the thin lens 1 of the first embodiment. Shown in FIG. 2C is a modulation transfer function diagram of the thin lens 1 of the first embodiment.

As can be seen from FIG. 2A, the thin lens 1 of the first embodiment has a field curvature between -0.01 in the meridian (Tangential) direction and sagittal direction for light with wavelengths of 0.810 μm, 0.830 μm, and 0.850 μm. mm to 0.045mm.

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

As can be seen from FIG. 2C, the thin lens 1 of the first embodiment has a wavelength range of 0.810 μm to 0.850 μm in the meridional (Tangential) direction and sagittal (Sagittal) direction, and the field of view height is 1.3608 mm, 1.8144mm, 2.2680mm, 2.4000mm, the spatial frequency is between 0lp/mm and 200lp/mm, and its modulation transfer function value 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 a lens configuration of a second embodiment of a 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 Optical sheet OF2. When imaging, the light from the object side is finally imaged on an imaging surface IMA2.

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

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

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

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

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

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 are} the same as 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 it will not be repeated here.

By using the lens, the aperture ST2, and the design satisfying at least one of the conditions (9) to (16), the thin lens 2 can effectively shorten the total lens length, correct aberrations, improve resolution, and resist environmental temperature changes.

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

The aspherical surface depression degree 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

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

Table 4 is the related parameter table of the aspherical surface of each lens in Table 3, where k is the conic constant and A~D is the aspherical coefficient.

Table 5 is the parameter values in Condition (9) to Condition (18) and the calculated values of Condition (9) to Condition (18). As can be seen from Table 5, the thin lens 2 of the second embodiment can satisfy 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, as can be seen from FIGS. 4A to 4C. Shown in FIG. 4A is a field curvature diagram of the thin lens 2 of the second embodiment. FIG. 4B is a distortion diagram of the thin lens 2 of the second embodiment. FIG. 4C is a modulation transfer function diagram of the thin lens 2 of the second embodiment.

As can be seen from FIG. 4A, the thin lens 2 of the second embodiment has a field curvature between -0.02 in the meridian (Tangential) direction and sagittal direction for the light with wavelengths of 0.810 μm, 0.830 μm, and 0.850 μm. mm to 0.08mm.

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

It can be seen from FIG. 4C that the thin lens 2 of the second embodiment has a wavelength range of 0.810 μm to 0.850 μm, respectively in the meridional (Tangential) direction and sagittal (Sagittal) direction, and the field of view height is 1.3608 mm, 1.8144mm, 2.2680mm, 2.4000mm, the spatial frequency is between 0lp/mm and 200lp/mm, and its modulation transfer function value 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 fall within the scope of the present invention.

Although the present invention has been disclosed as above in an embodiment, it is not intended to limit the present invention. Anyone who is familiar with this art can make various changes and modifications within the spirit and scope of the present invention, so the protection of the present invention The scope shall be determined by the scope of the attached patent application.

Claims (10)

A thin lens includes: a first lens with positive refractive power, the first lens including a convex surface facing an image side; a second lens with positive refractive power, the second lens including a concave surface facing the image side; a third lens With positive refractive power, the third lens includes a concave surface facing an object side and a convex surface facing the image side; and a fourth lens having positive refractive power; wherein the first lens, the second lens, the third lens, and the first lens The four lenses are arranged in sequence along the optical axis from the object side to the image side. A thin lens, including: a first lens with positive refractive power, the first lens includes a convex surface toward an image side; a second lens with positive refractive power, the second lens includes a convex surface toward an object side and a concave surface toward the An image side; a third lens with positive refractive power, the third lens including a concave surface facing the object side and a convex surface facing the image side; an aperture; and a fourth lens having positive refractive power; wherein the first lens, the first The two lenses, the third lens, the aperture, and the fourth lens are sequentially arranged along the optical axis from the object side to the image side. The thin lens as described in item 2 of the patent application range, wherein the first lens further includes a convex surface facing the object side, the thin lens satisfies the following condition: f ₂₃₄ >0; wherein, f _{234 is} the second lens, the One of the effective focal lengths of the combination of the third lens and the fourth lens. The thin lens as described in item 1 of the patent application scope further includes an aperture disposed between the third lens and the fourth lens. The thin lens as described in item 1 of the patent application range, wherein the first lens further includes a convex surface facing the object side. The thin lens as claimed in any one of claims 2 to 5, wherein the fourth lens includes a convex surface facing the object side and a concave surface facing the image side. The thin lens as described in any of claims 2 to 4 of the patent application, wherein the thin lens satisfies the following conditions: 0.3<SL/TTL<0.8; wherein, SL is the aperture to an imaging plane on the A pitch on the optical axis, TTL is a pitch on the optical axis from the object side of the first lens to the imaging plane. The thin lens as described in any one of claims 1 to 5 of the patent application scope, wherein 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. The thin lens as described in any of claims 1 to 5 of the patent application scope, wherein 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 one of the first lenses, 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 as described in any one of claims 1 to 5 of the patent scope, wherein the thin lens satisfies the following conditions: R ₁₂ /f ₁ <0; wherein, R _{12 is an image of} the first lens The radius of curvature of one of the sides, f _{1 is} the effective focal length of one of the first lenses.