An aspherical multi-cemented optical 5X zoom lens

Abstract

The present invention belongs to the technical field of optical lenses, and specifically relates to an aspherical multi-cemented optical 5X zoom lens. A first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens are sequentially arranged along the optical axis from the object plane to the image plane. A light-shielding paper is arranged between the third lens and the fourth lens. The second lens and the third lens are plastic-cemented lenses, and the fifth lens and the sixth lens are plastic-cemented lenses. The focal lengths of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens are negative, negative, positive, positive, negative, and positive in sequence. Through the aspherical multi-cemented design, the combination of glass and cemented aspheres is 2G4P, achieving a 5X zoom function and a non-focus-shifting function at high and low temperatures (high temperature +80 °C, low temperature -40 °C), and the resolving power reaches more than 4 million.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical lenses, and particularly relates to an aspherical multi-cemented optical 5X zoom lens. Background Art

[0002] A zoom lens is a camera lens that can change the focal length within a certain range to obtain different field angles of view of different widths, different sizes of images, and different ranges of scenery. Without changing the shooting distance, a zoom lens can change the shooting range by changing the focal length, so it is very beneficial for picture composition. Since a zoom lens can serve as several fixed-focus lenses, it not only reduces the number of photographic equipment carried when traveling, but also saves the time for changing lenses.

[0003] Over time, the zoom lenses on the market basically have an optical focal length between 2.7 mm and 13.5 mm, and the FNo. is between 1.6 and 3.2. They do not defocus at high and low temperatures (high temperature +80 °C, low temperature -40 °C), have low illuminance, and the infrared defocus amount is within 0.01, which can meet the requirements! However, the number of lens elements is very large. In the early stage of development, there were 10 pieces of glass, and in the later stage, it was basically fixed at 9 pieces of glass-plastic hybrid. Since there are many lens elements, there are also many unstable factors during assembly, so the yield rate is low, the assembly speed is correspondingly slow, and the cost is relatively high, which is not conducive to the current market competition. Summary of the Invention

[0004] The purpose of the present invention is to provide an aspherical multi-cemented optical 5X zoom lens for the problems existing in the prior art. Through the aspherical multi-cemented design, a combination of glass and cemented aspherical lenses, i.e., 2G4P, realizes the 5X zoom function, realizes the function of not defocusing at high and low temperatures (high temperature +80 °C, low temperature -40 °C), and the resolution reaches more than 4 million.

[0005] The technical solution of the present invention is as follows:

[0006] An aspherical multi-cemented optical 5X zoom lens is provided with a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens in sequence along the optical axis from the object plane to the image plane. A light-shielding paper is arranged between the third lens and the fourth lens. The second lens and the third lens are plastic cemented lenses, and the fifth lens and the sixth lens are plastic cemented lenses. The focal lengths of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens are negative, negative, positive, positive, negative, and positive in sequence.

[0007] Specifically, the second lens, the third lens, the fifth lens, and the sixth lens are plastic aspherical lenses; the first lens and the fourth lens are glass spherical lenses.

[0008] Specifically, the first lens is a negative meniscus lens, the second lens is a negative meniscus lens, the third lens is a biconvex lens, the fourth lens is a biconvex lens, the fifth lens is a negative meniscus lens, and the sixth lens is a biconvex lens.

[0009] Specifically, the first lens is a high refractive index and low dispersion lens satisfying Nd = 1.69; Vd = 54.7, and the second lens is a low dispersion lens satisfying the condition Vd = 55.7.

[0010] Specifically, the third lens is a high dispersion lens satisfying Vd = 21.5; the fourth lens is a low dispersion lens satisfying Vd = 68.6.

[0011] Specifically, the fifth lens is a high dispersion lens satisfying Vd = 21.5, and the sixth lens is a low dispersion lens satisfying Vd = 55.7.

[0012] Specifically, the second lens and the third lens are cemented, and the fifth lens and the sixth lens are cemented.

[0013] The beneficial effects of the present invention are as follows: 1. The 5X zoom lens provided by the present invention consists of G1, P2, and P3 forming a focusing group, and G4, P5, and P6 forming a zooming group. The overall focal length of the lens is changed by changing the distance between the two groups, realizing the 5X zoom function; 2. Through the P2 / P3 and P5 / P6 plastic aspherical lenses, the combination of one negative and one positive compensates for the deformation and refractive index change generated at high and low temperatures, realizing no focus shift at high and low temperatures (high temperature +80°C, low temperature -40°C); 3. By using the cemented aspherical lenses of P2 / P3 and P5 / P6, spherical aberration, coma, astigmatism, field curvature and other aberrations can be effectively corrected, thereby improving the resolution quality of the lens. G4 uses a low refractive index and low dispersion material (Nd = 1.60, vd = 70.6), which can further optimize spherical aberration and coma, so as to achieve an ideal resolution, realizing a resolution of more than 4 million; 4. Generally, to achieve the requirements of a 3X zoom lens, the lens does not have a focus shift at high and low temperatures, and the total number of glass lenses needs to reach more than 9. The lenses on the market use a glass-plastic hybrid design and do not achieve the effect. Generally, 6G3P or 4G5P are used. Due to the use of more lenses, the tolerance accumulation is sensitive and the assembly requirements are high. However, the present invention uses 1G2P in the front group and 1G2P in the rear group, and the aspherical lenses are cemented lenses, and the number is reduced to 6. At the same time, because the number of lenses is reduced, the assembly requirements are greatly reduced, realizing the cost reduction requirement.

[0014] The optical lens of the present invention is a 5X zoom lens with a focal length of 2.7 - 13.5, and can also ensure high resolution; it adopts a temperature compensation design and can work in an environment of -40°C to +80°C without defocusing; it adopts the form of a combination of glass and plastic with plastic aspherical lenses glued together, which not only ensures the performance of the optical system, but also can reduce the processing cost of parts, simplify the structure, reduce the weight, and is also conducive to mass production, meeting the market demand; while using low-dispersion materials, it can also improve the image quality of the picture. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a schematic structural diagram of the present invention;

[0016] Figure 2 is the MTF curve diagram of the wide-angle end of the zoom lens of the present invention;

[0017] Figure 3 is the MTF curve diagram of the telephoto end of the zoom lens of the present invention;

[0018] Figure 4 The field curvature and distortion curve diagram of the wide-angle end of the zoom lens of the present invention;

[0019] Figure 5 is the field curvature and distortion curve diagram of the telephoto end of the zoom lens of the present invention;

[0020] Figure 6 is the lateral chromatic aberration curve diagram of the wide-angle end of the zoom lens of the present invention;

[0021] Figure 7 is the lateral chromatic aberration curve diagram of the telephoto end of the zoom lens of the present invention;

[0022] Figure 8 is the spherical aberration curve diagram of the wide-angle end of the zoom lens of the present invention;

[0023] Figure 9 is the spherical aberration curve diagram of the telephoto end of the zoom lens of the present invention.

[0024] 1 First lens, 2 Second lens, 3 Third lens, 4 Fourth lens, 5 Fifth lens, 6 Sixth lens. DETAILED DESCRIPTION OF THE INVENTION

[0025] As Figure 1 shown is a schematic structural diagram of an aspherical multi-glued optical 5X zoom lens provided by the present invention. A first lens 1, a second lens 2, a third lens 3, a fourth lens 4, a fifth lens 5, and a sixth lens 6 are sequentially arranged along the optical axis from the object plane to the image plane. A light-shielding paper is arranged between the third lens 3 and the fourth lens 4.

[0026] The second lens 2 and the third lens 3 are plastic cemented lenses, and the fifth lens 5 and the sixth lens 6 are plastic cemented lenses; the focal lengths of the first lens 1, the second lens 2, the third lens 3, the fourth lens 4, the fifth lens 5, and the sixth lens 6 are negative, negative, positive, positive, negative, and positive in sequence.

[0027] The second lens 2, the third lens 3, the fifth lens 5, and the sixth lens 6 are plastic aspherical lenses; the first lens 1 and the fourth lens 4 are glass spherical lenses. The first lens 1 is a negative meniscus lens, the second lens 2 is a negative meniscus lens, the third lens 3 is a biconvex lens, the fourth lens 4 is a biconvex lens, the fifth lens 5 is a negative meniscus lens, and the sixth lens 6 is a biconvex lens.

[0028] The first lens is a high refractive index and low dispersion lens satisfying Nd = 1.69; Vd = 54.7, and the second lens is a low dispersion lens satisfying the condition Vd = 55.7. The third lens is a high dispersion lens satisfying Vd = 21.5; the fourth lens is a low dispersion lens satisfying Vd = 68.6. The fifth lens is a high dispersion lens satisfying Vd = 21.5, and the sixth lens is a low dispersion lens satisfying Vd = 55.7. The second lens and the third lens are cemented, and the fifth lens and the sixth lens are cemented.

[0029] The 5X zoom lens provided by the present invention consists of G1, P2, and P3 that form a focusing group, and G4, P5, and P6 that form a zooming group. The overall focal length of the lens is changed by changing the distance between the two groups to achieve the 5X zoom function; 2 through the P2 / P3 and P5 / P6 plastic aspherical lenses, with a negative and a positive combination to compensate for the deformation and refractive index change generated at high and low temperatures, so as to achieve no focus shift at high and low temperatures (high temperature +80°C, low temperature -40°C). Generally, to meet the requirements of a 3X zoom lens, the lens should not have focus shift at high and low temperatures, and the total number of glass lenses should reach more than 9; the lenses on the market use a glass-plastic hybrid design and do not achieve the effect. Generally, 6G3P or 4G5P are used. Due to the use of more lenses, the tolerance accumulation is sensitive and the assembly requirements are high. While the present invention uses 1G2P for the front group and 1G2P for the rear group, and the aspherical lenses are cemented lenses, the number is reduced to 6, and at the same time, because the number of lenses is reduced, the assembly requirements are greatly reduced to meet the cost reduction requirements.

[0030] By using the cemented aspherical lenses of P2 / P3 and P5 / P6, spherical aberration, coma, astigmatism, field curvature and other aberrations can be effectively corrected, thereby improving the resolution quality of the lens. G4 uses a low refractive index and low dispersion material (Nd = 1.60 vd = 70.6), which can further optimize spherical aberration and coma, so as to achieve an ideal resolving power and the resolving power reaches more than 4 million.

[0031] The optical zoom lens provided by the present invention is a 5X zoom lens with a focal length of 2.7 - 13.5, and can also ensure high resolution; it adopts a temperature compensation design and can work in an environment of -40°C to +80°C without defocusing; it adopts a form of combining glass and plastic with plastic aspherical lenses glued together, which not only ensures the performance of the optical system, but also can reduce the processing cost of parts, simplify the structure, reduce the weight, and is also conducive to mass production, meeting the market demand; while using low-dispersion materials, it can also improve the image quality of the picture.

[0032] Such as Figure 2 is the MTF curve graph of the wide-angle end of the zoom lens of the present invention; Figure 3 is the MTF curve graph of the telephoto end of the zoom lens of the present invention; Figure 4 The field curvature and distortion curve graph of the wide-angle end of the zoom lens of the present invention; Figure 5 is the field curvature and distortion curve graph of the telephoto end of the zoom lens of the present invention; Figure 6 is the lateral chromatic aberration curve graph of the wide-angle end of the zoom lens of the present invention; Figure 7 is the lateral chromatic aberration curve graph of the telephoto end of the zoom lens of the present invention; Figure 8 is the spherical aberration curve graph of the wide-angle end of the zoom lens of the present invention; Figure 9 is the spherical aberration curve graph of the telephoto end of the zoom lens of the present invention. The following table is:

[0033] # Type Comment Radius Thickness Material 2 Standard G1 21.00 1.00 1.69; 54.8 3 Standard 6.55 5.73 4 Even Aspheric Surface P2 -10.35 1.65 1.53; 55.7 5 Even Aspheric Surface P3 13.50 2.02 1.635; 23.9 6 Even Aspheric Surface -65.03 11.86 - 1.91 (Variable) 7 Standard Diaphragm Infinity 8.53 - 0.485 (Variable) 8 Standard G4 8.43 3.16 1.59; 68.5 9 Standard -110.94 0.07 10 Even Aspheric Surface P5 43.75 3.09 1.635; 23.9 11 Even Aspheric Surface P6 5.66 4.05 1.53; 55.7 12 Even Aspheric Surface -12.80 8.61 - 16.67 (Variable) 13 Standard CG Infinity 0.70 1.51; 64.2 14 Standard Infinity 0.10 15 Standard Infinity 0.00

[0034] K A4 A6 A8 A10 1.51E+00 3.81E-04 -1.68E-05 1.04E-06 -1.41E-08 -4.30E+00 -2.40E-04 5.97E-05 1.07E-06 -6.98E-07 9.48E+01 -2.23E-05 1.72E-05 -2.09E-06 1.14E-07 -1.00E+02 -4.37E-04 2.24E-05 -2.84E-06 1.53E-07 5.17E-01 -1.98E-03 5.61E-05 -1.55E-05 1.26E-06 -2.41E+01 -7.77E-04 -3.84E-05 1.87E-05 -1.70E-06

[0035] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that: still can modify the specific implementation manners of the present invention or perform equivalent replacements for some technical features; without departing from the spirit of the technical solutions of the present invention, they should all be covered within the scope of the technical solutions claimed by the present invention.

Claims

1. An aspherical multi-cemented optical 5X zoom lens, characterized in that, A first lens (1), a second lens (2), a third lens (3), a fourth lens (4), a fifth lens (5) and a sixth lens (6) are sequentially arranged along the optical axis from the object plane to the image plane. A light-shielding paper is arranged between the third lens (3) and the fourth lens (4). The second lens (2) and the third lens (3) are plastic cemented lenses, and the fifth lens (5) and the sixth lens (6) are plastic cemented lenses. The focal lengths of the first lens (1), the second lens (2), the third lens (3), the fourth lens (4), the fifth lens (5) and the sixth lens (6) are negative, negative, positive, positive, negative and positive in sequence. The first lens (1) is a negative meniscus lens, the second lens (2) is a negative meniscus lens, the third lens (3) is a biconvex lens, the fourth lens (4) is a biconvex lens, the fifth lens (5) is a negative meniscus lens, and the sixth lens (6) is a biconvex lens. The second lens (2), the third lens (3), the fifth lens (5) and the sixth lens (6) are plastic aspherical lenses. The first lens (1) and the fourth lens (4) are glass spherical lenses.

2. The aspherical multi-cemented optical 5X zoom lens according to claim 1, wherein, The first lens is a high-refractive-index and low-dispersion lens satisfying Nd = 1.69; Vd = 54.7, and the second lens is a low-dispersion lens satisfying the condition Vd = 55.

7.

3. The aspherical multi-cemented optical 5X zoom lens according to claim 1, characterized in that, The third lens is a high-dispersion lens satisfying Vd = 21.5; the fourth lens is a low-dispersion lens satisfying Vd = 68.

6.

4. The aspherical multi-cemented optical 5X zoom lens according to claim 1, wherein The fifth lens is a high-dispersion lens satisfying Vd = 21.5, and the sixth lens is a low-dispersion lens satisfying Vd = 55.

7.

5. The aspherical multi-cemented optical 5X zoom lens according to claim 1, wherein The second lens and the third lens are cemented, and the fifth lens and the sixth lens are cemented.

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