TWI769032B - Lens assembly - Google Patents

Abstract

An lens assembly includes five lens elements which are, in order from an object side to an image side: a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element. The first lens element has negative refractive power, and the object-side surface of the first lens element is convex in a paraxial region thereof, and the image-side surface of the first lens element is concave in a paraxial region thereof. The second lens element has negative refractive power, and both the object-side surface and image-side of the second lens element are concave in a paraxial region thereof. The third lens element has positive refractive power, and both the object-side surface and image-side of the second lens element are convex in a paraxial region thereof. The fourth lens element has negative refractive power, and the object-side surface of the first lens element is convex in a paraxial region thereof. The fifth lens element has negative refractive power, and both the object-side surface and image-side of the second lens element are concave in a paraxial region thereof. When specific conditions are satisfied, the lens assembly meets the requirement of projecting patterns at a distance of 13m~26m.

Description

lens module

The present invention relates to a lens module, in particular to a lens module for a shooting distance of 13m to 26m.

In today's society, there is a need to take pictures anytime, anywhere. Whether it is landscapes, static objects, dynamic objects or selfies, the requirements for camera quality will also increase. Wide-angle lenses with a wide range, commonly used shooting lenses, and telephoto lenses with farther shooting distances, and when shooting objects and landscapes at a longer distance, a telephoto lens is required to meet the needs of the photographer, such as shooting distant landscapes, bird watching When taking pictures of birds, seeing rare species in the distance, etc., due to different reasons, it is necessary to keep a long distance from the photographed objects, so there are various problems such as distance and environment during shooting, resulting in insufficient clarity and depth of field. meet specific needs.

As for the shooting lens group, as the playback quality of the playback media improves, the shooting quality also improves. The shooting quality of the lens group can achieve wider range shooting, longer-distance shooting, shooting of specific objects, and shooting of different shooting needs according to different shooting needs. The quality of finished products has been continuously developing in the industry.

Traditional camera lenses can be divided into fixed focal length lenses and zoom lenses according to the needs of the photographer. Fixed focal length lenses are fixed focal lengths, and different lenses need to be carried for different distances. .

Since the development of digital cameras, there are also digital single-lens cameras with interchangeable lenses. The selection of lenses for digital cameras begins to increase, and the specific lens corresponding to the focal length can be changed according to the needs of taking pictures.

Therefore, in terms of technical issues such as the definition, depth of field, light and other technical issues of the finished product, there are also different numbers of lens combinations in the lens group design to achieve specific purposes. Using a combination of three groups of lenses, four groups of lenses, five groups of lenses or a combination of more lenses can improve the clarity and depth of field of photos after general shooting and wide-angle shooting, and continue to improve the quality of the finished product.

However, with the development and demand of human technology, shooting products including mobile phones and digital cameras are moving towards the direction of lightness, thinness and portability. Therefore, the lens combination cannot only improve the shooting quality by increasing the number of lenses, but must take into account the volume problem. Therefore, the design aspect The lens group often changes the lens combination, material, aperture and other methods to improve the quality of the finished product.

The lens combination reference includes parameters such as focal length, refractive index, lens concave-convex combination, curvature radius, lens thickness, degree of dispersion, refractive index and Abbe number, so the following parameters will be considered during manufacturing.

Among them, the dispersion number affects the imaging quality. The higher the dispersion degree, the lower the clarity, and vice versa, while the refractive index and Abbe number will affect the dispersion degree. The refractive index and the dispersion degree are positively correlated, which means that the higher the refractive index is. , the higher the degree of dispersion, the lower the clarity, and the Abbe number is negatively correlated with the degree of dispersion, which means that the higher the Abbe number, the lower the degree of dispersion, and the higher the clarity.

Among the commonly used formulas for lenses, the lens maker's formula can know that the thickness of the lens, the material of the lens, the radius of curvature of the object side of the lens and the radius of curvature of the image side of the lens all affect the focal length of the lens.

The lens object side and lens image side structures affect the lens refractive power, and the lens refractive power affects the lens focal length.

In general lenses, the convex lens is used for focusing, the concave lens is used for divergence, the refractive index of the convex lens is positive on the object side of the lens, and the refractive index of the concave lens is negative. For non-identical lenses on the image side, the values of the two should be compared.

Referring to patent TWI707156B, its specification discloses that its patent protection scope includes values such as positive or negative refractive power of each lens, lens Abbe number, refractive index, lens thickness, radius of curvature, focal length, distance between lenses, etc. The first lens is positive refractive power, the second lens is negative refractive power, and the fifth lens is negative refractive power.

Refer to patent TWI607235B, its specification discloses that its patent protection scope includes that the respective refractive power of the lens is positive or negative, the lens is convex or concave at the near optical axis, the thickness of the respective lenses, the air gap between the lenses, the optical The value of the total thickness on the axis, the dispersion coefficient, etc., the first lens has a positive refractive power, the third lens has a positive refractive power, and the fifth lens has a negative refractive power.

The present invention provides a lens module, which sequentially includes a first lens with negative refractive power, a second lens with negative refractive power, a third lens with positive refractive power, and a The fourth lens with negative refractive power and the fifth lens with negative refractive power, wherein the object-side surface of the first lens is convex at the near-optical axis, the image-side near-optical axis is concave, and the second lens is at the object-side and image-side near-optical axes. All are concave, the object side and the image side of the third lens are convex at the near optical axis, the fourth lens is convex at the near optical axis, the fifth lens is concave at the object side and the near optical axis of the image side, and the light follows the present invention. It goes through two divergences in sequence, then a focus, and finally, through two divergences, the image is placed on the glass of the rear digital micro-mirror device, increasing the resolution of the image from a distance of 13m to 26m.

One of the objectives of the present invention is to provide a lens module with only five internal lens combinations, the specific lens combination can maintain good shooting quality at a distance between 13m and 26m, and the combination of different positive and negative refractive forces can improve the lens module The resolution of the group.

For the above purpose, the present invention provides a lens module, which includes a first lens, a second lens, a third lens, a fourth lens, and a fifth lens from an object side to an image side.

The first lens has a first refractive power, the second lens has a second refractive power, the third lens has a third refractive power, the fourth lens has a fourth refractive power, and the fourth lens has a fourth refractive power. The five lenses have a fifth refractive power.

The first inflection force is a negative value, the second inflection force is a negative value, the third inflection force is a positive value, the fourth inflection force is a negative value, and the fifth inflection force is a negative value.

A first object-side surface of the first lens is convex at the near-optical axis, a first image-side surface of the first lens is a first concave near the optical axis, and a second object-side surface of the second lens is A second concave surface is located near the optical axis, a third concave surface is located near the optical axis of a second imaging surface of the second lens, and the third A third object-side surface of one of the lenses is a second convex surface near the optical axis, a third imaging surface of the third lens is a third convex surface near the optical axis, and a fourth object-side surface of the fourth lens A fourth convex surface is located at the near optical axis, a fourth concave surface is located at the near optical axis of a fifth object side surface of a fifth lens, and a fifth image side surface near the optical axis is a fifth lens. Concave.

The second Abbe number of one of the second lenses is Vd2, the third Abbe number of one of the third lenses is Vd3, and the fourth Abbe number of one of the fourth lenses is Vd4, which satisfy the following conditions: 131.21<Vd2 +Vd3+Vd4<131.37.

The first thickness of the first lens is CT1, the second thickness of the second lens is CT2, the third thickness of the third lens is CT3, the fourth thickness of the fourth lens is CT4, the The fifth thickness of one of the five lenses is CT5, and a second air gap G23 between the second lens and the third lens satisfies the following conditions: CT5/CT4=0.367 and 0.59<(CT1+CT2+CT4+CT5)/ (CT3+G23)<0.60.

The total thickness of the first lens, the second lens, the third lens, the fourth lens and the fifth lens is ALT, the air gap between the first lens and the second lens, the second lens and the fifth lens The total Gaa among the three lenses, the third lens, the fourth lens, the fourth lens and the fifth lens satisfies the following condition: 0.96<ALT/Gaa<0.97.

In the lens module, the highest refractive index of all lenses is Nmax, which satisfies the following conditions: 1.67<Nmax<1.85.

In this lens module, the lowest Abbe number among all lenses is Vdmin, which satisfies the following conditions: 23.77<Vdmin<49.60.

In an embodiment of the present invention, wherein, the thickness CT2 of the second lens, the thickness CT3 of the third lens, a first air gap G12 on the optical axis of the first lens and the second lens, which satisfy the following conditions : 5.56<(G12+CT3)/CT2<5.57.

In an embodiment of the present invention, the second thickness CT2 and the third thickness CT3 satisfy the following condition: 3.30<CT3/CT2<3.37.

In one embodiment of the present invention, the second thickness CT2 and the total thickness of the first lens to the fifth lens AL satisfy the following condition: 9.10<ALT/CT2<9.33.

In an embodiment of the present invention, wherein, the fourth lens thickness CT4, a fourth air gap G45 on the optical axis of the fourth lens and the fifth lens satisfies the following conditions: 3.23<CT4/G45< 3.25.

In one embodiment of the present invention, the thickness CT5 of the fifth lens and the sum of the air gaps on the optical axis of the first lens to the fifth lens Gaa satisfy the following conditions: 11.58<Gaa/CT5<11.82.

In one embodiment of the present invention, the first lens thickness CT1, the second lens thickness CT2, the fourth lens thickness CT4, the fifth lens thickness CT5, the first lens to the fifth lens are in the light The sum of the air gaps on the shaft, Gaa, satisfies the following conditions: 0.85<(T1+T2+T4+T5)/Gaa<0.88.

1: Lens module

2: Object side

3: Image side

11: The first lens

111: The first object side

1111: First Convex

112: The first image side

1121: first concave surface

12: Second lens

121: Second Object Side

1211: Second Concave

122: Second image side

1221: Third Concave

13: The third lens

131: Third Object Side

1311: Second Convex

132: Third image side

1321: Third Convex

14: Fourth lens

141: Fourth Object Side

1411: Fourth Convex

15: Fifth lens

151: Fifth Object Side

1511: Fourth Concave

152: Fifth image side

1521: Fifth Concave

16: Digital Micromirror Device

I: Optical axis

D1: first inflection force

D2: Second inflection force

D3: The third inflection force

D4: Fourth inflection force

D5: Fifth inflection force

Vd2: Second Abbe number

Vd3: the third Abbe number

Vd4: Fourth Abbe number

Vdmin: Minimum lens Abbe number

Nmax: the maximum refractive index of the lens

CT1: first thickness

CT2: Second Thickness

CT3: Third Thickness

CT4: Fourth thickness

CT5: Fifth thickness

ALT: total lens thickness

G12: First Air Gap

G23: Second Air Gap

G45: Fourth Air Gap

Gaa: Sum of air gaps between lenses

Fig. 1 is a schematic diagram of the configuration of an embodiment of the present invention.

In order to enable your reviewers to have a further understanding and understanding of the features of the present invention and the effects achieved, I would like to accompany the examples and descriptions. Insufficient and limited depth of field of the macro lens, if the above problems are solved, the quality of the finished product will be improved when shooting at a distance of 13~26m.

Given the problem. Accordingly, the present invention proposes a lens module to solve the problems caused by the prior art.

In the following, the characteristics and matching structures included in the present invention will be further explained: each lens is defined according to the formula of the mirror maker: 1/f=(n-1)(1/R1-1/R2)+[(n-1 ) ² /n](t/R1R2), where f is the focal length of the lens, n is the refractive index of the material, R1 is the radius of curvature of the object side of the lens, R2 is the radius of curvature of the image side of the lens, and t is the thickness of the lens. Find the focal length of each lens.

Please refer to FIG. 1, which is a schematic diagram of the configuration of a lens module 1. The lens module 1 includes a first lens 11, a second lens 12, and a third lens from an object side 2 to an image side 3, respectively. The lens 13 , a fourth lens 14 , and a fifth lens 15 .

Continuing from the above, as shown in the figure, in this embodiment, light passes through the first lens 11 , the second lens 12 , the third lens 13 , the fourth lens 14 and the fifth lens 15 , and converges on a digital microcomputer on the mirror device 16.

Wherein, a first convex surface 1111 on the surface of the first object side 111 of the first lens 11 is a first convex surface 1111, and a surface of the first image side 112 of the first lens 11 is a first concave surface at the near optical axis I 1121, a second object side 121 surface of the second lens 12 is a second concave surface 1211 at the near optical axis I, and a second image side 122 surface of the second lens 12 is a third concave surface near the optical axis I 1221, one of the third object side 131 surface of the third lens 13 is a second convex surface 1311 at the near optical axis, and one of the third lens 13 is a third image side 132 surface near the optical axis I is a third convex surface 1321, a fourth object side 141 surface of the fourth lens 14 is a fourth convex surface 1411 at the near optical axis, and a fifth object side 151 surface of the fifth lens 15 is a fourth concave surface I near the optical axis 1511, a fifth concave surface 1521 at the near optical axis I of the fifth image side 152 surface of the fifth lens 15.

The first lens 11 has a first refractive power D1, the second lens 12 has a second refractive power D2, the third lens 13 has a third refractive power D3, and the fourth lens 14 has a fourth The refractive power D4, the fifth lens 15 has a fifth refractive power D5.

Wherein, the first inflection force D1 is a negative value, the second inflection force D2 is a negative value, the third inflection force D3 is a positive value, the fourth inflection force D4 is a negative value, and the fifth inflection force is a negative value D5 value.

Continuing the above, the second lens 12 and the second Abbe number are Vd2, the third lens 13 and the third Abbe number are Vd3, and the fourth lens 14 and the fourth Abbe number are Vd4, which satisfy the following conditions: 131.21 <Vd2+Vd3+Vd4<131.37.

Continuing from the above, a first thickness of the first lens 11 on the optical axis I is CT1, a second thickness of the second lens 12 on the optical axis I is CT2, and the third lens 13 is on the optical axis I. A third thickness is CT3, a fourth thickness of the fourth lens 14 on the optical axis I is CT4, a fifth thickness of the fifth lens 15 on the optical axis I is CT5, the second lens 12 and the A second air gap G23 on the optical axis I between the third lenses 13, which satisfies the following conditions: CT5/CT4=0.367 and 0.59<(CT1+CT2+CT4+CT5)/(CT3 +G23)<0.60.

Continuing from the above, in the lens module 1, the total Gaa of the four air gaps from the first lens 11 to the fifth lens 15 on the optical axis I, the total thickness of the first lens 11 to the fifth lens 15 is ALT, which satisfies the following conditions: 0.96<ALT/Gaa<0.97.

Continuing from the above, the maximum value of refractive index in all lenses in the lens module 1 is Nmax, and in this lens module, the minimum value of Abbe ratio in all lenses is Vdmin, which satisfy the following conditions: 1.67<Nmax<1.85 and 23.77<Vdmin <49.60.

Continuing the above, wherein, the second lens thickness CT2, the third lens thickness CT3 and a first air gap G12 on the optical axis I of the first lens 11 and the second lens 12 satisfies the following conditions: 5.56< (G12+CT3)/CT2<5.57.

Continuing from the above, wherein, the second lens thickness CT2 and the third lens thickness CT3 satisfy the following conditions: 3.30<CT3/CT2<3.37.

Continuing from the above, wherein, the second thickness CT2 and the total thickness of the first lens to the fifth lens ALT satisfy the following conditions: 9.10<ALT/CT2<9.33.

Continuing from the above, wherein the fourth lens 14 and the fifth lens 15 have a fourth air gap G45 on the optical axis I, which satisfies the following conditions: 3.23<CT4/G45<3.25.

Continuing from the above, wherein, the thickness CT5 of the fifth lens, the sum of the air gaps from the first lens to the fifth lens on the optical axis Gaa, which satisfies the following condition: Gaa/CT5=11.905.

Continuing from the above, wherein, the first lens thickness CT1, the second lens thickness CT2, the third lens thickness CT3, the fourth lens thickness CT4, the fifth lens thickness CT5, the first lens to the fifth lens are in The sum of the air gaps on the optical axis, Gaa, satisfies the following conditions: 0.96<(CT1+CT2+CT3+CT4+CT5)/Gaa<0.97.

Continuing from the above, the lens module 1 has a pattern projection distance of 13-26m, an average reflectivity of less than 0.5%, and is suitable for a wavelength range of 420nm-680nm.

Referring to FIG. 1, a first embodiment of a lens module 1 of the present invention includes a first lens 11, a second lens 12, and a third lens in sequence along the optical axis I from an object side 2 to an image side 3 The lens 13 , a fourth lens 14 , a fifth lens 15 and a digital micro-mirror device 16 .

The first lens 11 has a first object side 111 and a first image side 112, the first object side 111 has a first convex surface 1111, the first image side 112 has a first concave surface 1121, the first The radius of curvature of a convex surface 1111 is 31.03 mm, the radius of curvature of the first concave surface 1121 is 70.78 mm, and the first lens 11 has a first refractive power D1 , which is a negative value.

The second lens 12 has a second object side 121 and a second image side 122, the second object side 121 has a second concave surface 1211, the second image side 122 has a third concave surface 1221, and the first The radius of curvature of the second concave surface 1211 is 59.07 mm, the radius of curvature of the third concave surface 1221 is 35.88 mm, the second lens 12 has a second refractive power D2, and the second refractive power D2 is negative.

The third lens 13 has a third object side 131 and a third image side 132, the third object side 131 has a second convex surface 1311, the third image side 132 has a third convex surface 1321, the third The curvature radius of the two convex surfaces 1311 is 118.07 mm, and the curvature radius of the third convex surface 1321 is 42.69 mm. The third lens 13 has a third refractive power D3, and the third refractive power D3 is a positive value.

The fourth lens 14 has a fourth object side 141 , the fourth object side 141 has a fourth convex surface 1411 , the curvature radius of the fourth convex surface 1411 is 35.57 mm, and the fourth lens 14 has a fourth inflection Force D4, the fourth inflection force D4 is negative.

The fifth lens 15 has a fifth object side 151 and a fifth image side 152, the fifth object side 151 has a fourth concave surface 1511, the fifth image side 152 has a fifth concave surface 1521, The curvature radius of the four concave surfaces 1511 is 129.48mm, the curvature radius of the fifth concave surface 1521 is 70.94mm, the fifth lens 11 has a fifth refractive power D5, and the fifth refractive power D5 is negative.

Wherein, a first thickness CT1 of the first lens 11 on the optical axis I is 4.67 mm, a second thickness CT2 of the second lens 12 on the optical axis I is 2.50 mm, and the third lens 13 is on the optical axis. A first thickness CT3 on I is 8.33mm, a fourth thickness CT4 of the fourth lens 14 on the optical axis I is 5.54mm, and a fifth thickness CT5 of the fifth lens 15 on the optical axis I is 2.00 mm.

The second Abbe number Vd2 of the second lens 12 is 32.10, the third Abbe number Vd3 of the third lens 13 is 49.60, and the fourth Abbe number Vd4 of the fourth lens 14 is 49.60.

Wherein, a first air gap G12 of the first lens 11 and the second lens 12 on the optical axis I is 5.59 mm, and a second air gap G12 of the second lens 12 and the third lens 13 on the optical axis I The gap G23 is 16.41 mm, a fourth air gap G45 of the fourth lens 14 and the fifth lens 15 on the optical axis I is 1.71 mm, and the first lens 11 to the fifth lens 15 are on the optical axis I. The combined Gaa of the four air gaps is 23.81mm.

Therefore, the present invention is indeed novel, progressive and available for industrial use, and it should meet the requirements for patent application in my country's patent law.

However, the above descriptions are only preferred embodiments of the present invention, and are not intended to limit the scope of implementation of the present invention. All changes and modifications made in accordance with the shape, structure, features and spirit described in the scope of the patent application of the present invention are equivalent. , shall be included in the scope of the patent application of the present invention.

1: Lens module

2: Object side

3: Image side

11: The first lens

111: The first object side

1111: First Convex

112: The first image side

1121: first concave surface

12: Second lens

121: Second Object Side

1211: Second Concave

122: Second image side

1221: Third Concave

13: The third lens

131: Third Object Side

1311: Second Convex

132: Third image side

1321: Third Convex

14: Fourth lens

141: Fourth Object Side

1411: Fourth Convex

15: Fifth lens

151: Fifth Object Side

1511: Fourth Concave

152: Fifth image side

1521: Fifth Concave

16: Digital Micromirror Device

I: Optical axis

Claims (10)

A lens module includes a first lens, a second lens, a third lens, a fourth lens and a fifth lens in sequence from an object side to an image side; wherein, the first lens has a first lens a refractive power, a first object side surface of the first lens has a first convex surface near the optical axis, a first image side surface of the first lens has a first concave surface near the optical axis, the second lens It has a second refractive power, a second concave surface at the second object-side near-optical axis of the second lens, a third concave surface at the second image-measuring near-optical axis of the second lens, and the third lens It has a third refractive power, one of the third lens has a second convex surface at the near-optical axis of the third object side, one of the third lens has a third convex surface at the near-optical axis of the third image measurement, and the fourth lens has a third convex surface having a fourth refractive power, a fourth object-side surface of the fourth lens has a fourth convex surface at the near optical axis, the fifth lens has a fifth refractive power, and a fifth object-side low beam of the fifth lens The axis has a fourth concave surface, and a fifth image side surface of the fifth lens has a fifth concave surface near the optical axis; wherein, the first refractive power is negative, the second refractive power is negative, the The third refractive power is a positive value, the fourth refractive power is a negative value, and the fifth refractive power is a negative value; and wherein, the second lens-a second Abbe number is Vd2, the third lens-a third Abbe number is Vd2 The Bay number is Vd3, the fourth Abbe number of the fourth lens is Vd4, the first thickness of the first lens on the optical axis is CT1, the second thickness of the second lens on the optical axis is CT2, A third thickness of the third lens on the optical axis is CT3, a fourth thickness of the fourth lens on the optical axis is CT4, a fifth thickness of the fifth lens on the optical axis is CT5, and a fourth thickness of the fifth lens on the optical axis is CT5. There is a second air gap G23 on the optical axis between the second lens and the third lens. In the lens module, the total of four air gaps on the optical axis from the first lens to the fifth lens is Gaa. The total thickness of the first lens, the second lens, the third lens, the fourth lens and the fifth lens on the optical axis is ALT, which satisfies the following conditions: 131.21<Vd2+Vd3+Vd4<131.37; CT5 /CT4=0.367; 0.59<(CT1+CT2+CT4+CT5)/(CT3+G23)<0.60; 0.96<ALT/Gaa<0.97. The lens module according to claim 1, wherein the thickness CT2 of the second lens, the thickness CT3 of the third lens, and a first air gap G12 on the optical axis of the first lens and the second lens satisfy The following conditions: 5.56<(G12+CT3)/CT2<5.57. The lens module according to claim 1, wherein the second thickness CT2 and the third thickness CT3 satisfy the following conditions: 3.30<CT3/CT2<3.37. The lens module of claim 1, wherein the second thickness CT2 and the total thickness of the first lens to the fifth lens ALT satisfy the following condition: 9.10<ALT/CT2<9.33. The lens module according to claim 1, wherein the thickness CT4 of the fourth lens, a fourth air gap G45 on the optical axis of the fourth lens and the fifth lens satisfies the following conditions: 3.23<CT4/ G45<3.25. The lens module according to claim 1, wherein the thickness CT5 of the fifth lens and the sum of the air gaps on the optical axis of the first lens to the fifth lens Gaa satisfy the following condition: Gaa/CT5=11.905. The lens module of claim 1, wherein the first lens thickness CT1, the second lens thickness CT2, the third lens thickness CT3, the fourth lens thickness CT4, the fifth lens thickness CT5, the The sum of the air gaps from the first lens to the fifth lens on the optical axis is Gaa, which satisfies the following condition: 0.96<(CT1+CT2+CT3+CT4+CT5)/Gaa<0.97. The lens module according to claim 1, wherein the shooting distance of the lens module is between 13m and 26m. The lens module according to claim 1, wherein the average reflectivity of the lens module is less than 0.5%. The lens module according to claim 3, wherein the lens module is suitable for wavelengths ranging from 420nm to 680nm.

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