TWI529418B - Zoom lens - Google Patents

Description

Zoom lens

The present invention relates to a zoom lens.

Most of the current digital cameras and digital cameras are equipped with zoom lenses. With the demand of various applications, the zoom lens gradually goes to a high zoom magnification, but it is not easy to achieve high resolution performance under high zoom magnification.

In view of the above, it is a primary object of the present invention to provide a zoom lens that has a high zoom ratio but still has good optical performance.

The zoom lens of the present invention sequentially includes a first lens group having a negative refractive power, a second lens group having a positive refractive power, and a third lens group having a positive refractive power along the optical axis from the object side to the image side. The first lens group sequentially includes a first lens, a second lens, a third lens and a fourth lens having a negative refractive power from the object side to the image side along the optical axis, the first lens being a convex-concave lens and a convex surface thereof On the object side, the refractive power of the object side of the fourth lens is greater than the refractive power of the image side. The second lens group sequentially includes a fifth lens having a positive refractive power, a sixth lens having a positive refractive power, and a seventh lens having a negative refractive power along the optical axis from the object side to the image side.

The second lens is a biconcave lens, and the third lens is a lenticular lens.

The second lens group satisfies the following condition: 0.5<|β _2w |<0.9; wherein β _2w is the lateral magnification of the second lens group at the wide-angle end.

Wherein the second lens satisfies the following condition: Vd ₂ >80; wherein Vd ₂ is the Abbe coefficient of the second lens.

When the zoom lens is in focus, the first lens group moves in the optical axis direction.

The fifth lens is a cemented lens, the sixth lens is a single lens, and the seventh lens is a cemented lens.

When the zoom lens is zoomed from the wide-angle end to the telephoto end, the distance between the first lens group and the second lens group is reduced.

The zoom lens of the present invention may further include an aperture disposed between the first lens group and the second lens group.

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

1, 2, 3‧‧ ‧ zoom lens

G11, G21, G31‧‧‧ first lens group

L11, L21, L31‧‧‧ first lens

L12, L22, L32‧‧‧ second lens

L13, L23, L33‧‧‧ third lens

L14, L24, L34‧‧‧ fourth lens

G12, G22, G32‧‧‧ second lens group

L15, L25, L35‧‧‧ fifth lens

L16, L26, L36‧‧‧ sixth lens

L17, L27, L37‧‧‧ seventh lens

L151, L152, L251‧‧ lens

L252, L351, L352‧‧ lens

G13, G23, G33‧‧‧ third lens group

L18, L28, L38‧‧‧ eighth lens

L39‧‧‧ ninth lens

OA1, OA2, OA3‧‧‧ optical axis

ST1, ST2, ST3‧‧ ‧ aperture

OF1, OF2, OF3‧‧‧ Filters

IMA1, IMA2, IMA3‧‧‧ imaging surface

S11, S12, S13, S14, S15, S16, S17‧‧

S21, S22, S23, S24, S25, S26, S27‧‧

S31, S32, S33, S34, S35, S36, S37‧‧

S18, S19, S110, S111, S112, S113‧‧‧

S28, S29, S210, S211, S212, S213‧‧‧

S38, S39, S310, S311, S312, S313‧‧

S114, S115, S116, S117, S118, S119‧‧

S214, S215, S216, S217, S218, S219‧‧‧

S314, S315, S316, S317, S318, S319‧‧‧

S120, S121, S220, S221, S320, S321‧‧‧

S322, S323‧‧‧

D1 ₈₉ , D1 ₉₁₀ , D1 ₈₁₀ , D1 ₁₇₁₈ , D1 ₁₉₂₀ ‧‧‧ spacing

D2 ₈₉ , D2 ₉₁₀ , D2 ₈₁₀ , D2 ₁₇₁₈ , D2 ₁₉₂₀ ‧‧‧ spacing

D3 ₈₉ , D3 ₉₁₀ , D3 ₈₁₀ , D3 ₁₇₁₈ , D3 ₂₁₂₂ ‧‧‧ spacing

Fig. 1 is a schematic view showing a lens arrangement and an optical path at a wide angle end of a first embodiment of a zoom lens according to the present invention.

Fig. 2 is a schematic view showing a lens arrangement and an optical path at the intermediate end of the first embodiment of the zoom lens according to the present invention.

Fig. 3 is a schematic view showing a lens arrangement and an optical path at the telephoto end according to the first embodiment of the zoom lens of the present invention.

Fig. 4A is a longitudinal aberration diagram of the zoom lens of Fig. 1.

Fig. 4B is a field curvature diagram of the zoom lens of Fig. 1.

Fig. 4C is a distortion diagram of the zoom lens of Fig. 1.

Fig. 4D is a transverse light fan diagram of the zoom lens of Fig. 1.

Fig. 4E is a transverse light fan diagram of the zoom lens of Fig. 1.

Fig. 4F is a transverse light fan diagram of the zoom lens of Fig. 1.

Fig. 4G is a lateral chromatic aberration diagram of the zoom lens of Fig. 1.

Fig. 5A is a longitudinal aberration diagram of the zoom lens of Fig. 2.

Fig. 5B is a field curvature diagram of the zoom lens of Fig. 2.

Fig. 5C is a distortion diagram of the zoom lens of Fig. 2.

Fig. 5D is a transverse light fan diagram of the zoom lens of Fig. 2.

Fig. 5E is a transverse light fan diagram of the zoom lens of Fig. 2.

Fig. 5F is a transverse light fan diagram of the zoom lens of Fig. 2.

Fig. 5G is a lateral chromatic aberration diagram of the zoom lens of Fig. 2.

Fig. 6A is a longitudinal aberration diagram of the zoom lens of Fig. 3.

Fig. 6B is a field curvature diagram of the zoom lens of Fig. 3.

Fig. 6C is a distortion diagram of the zoom lens of Fig. 3.

Fig. 6D is a transverse light fan diagram of the zoom lens of Fig. 3.

Fig. 6E is a transverse light fan diagram of the zoom lens of Fig. 3.

Fig. 6F is a transverse light fan diagram of the zoom lens of Fig. 3.

Fig. 6G is a lateral chromatic aberration diagram of the zoom lens of Fig. 3.

Fig. 7 is a view showing a lens arrangement and an optical path at a wide angle end of a second embodiment of the zoom lens according to the present invention.

Figure 8 is a schematic view showing a lens arrangement and an optical path at the intermediate end of the second embodiment of the zoom lens according to the present invention.

Figure 9 is a schematic view showing a lens arrangement and an optical path at the telephoto end in accordance with a second embodiment of the zoom lens of the present invention.

Fig. 10 is a view showing a lens arrangement and an optical path at a wide angle end of a third embodiment of the zoom lens according to the present invention.

Figure 11 is a schematic view showing a lens arrangement and an optical path at the intermediate end of the third embodiment of the zoom lens according to the present invention.

Figure 12 is a schematic view showing a lens arrangement and an optical path at the telephoto end in accordance with a third embodiment of the zoom lens of the present invention.

Please refer to FIG. 1 , FIG. 2 and FIG. 3 . FIG. 1 is a schematic diagram of a lens arrangement and an optical path at a wide angle end according to a first embodiment of a zoom lens according to the present invention, and FIG. 2 is a view of a zoom lens according to the present invention. A lens configuration and an optical path diagram at an intermediate end of an embodiment, and a lens configuration and an optical path diagram at a telephoto end according to the first embodiment of the zoom lens according to the present invention. The zoom lens 1 sequentially includes a first lens group G11, an aperture ST1, a second lens group G12, a third lens group G13, and a filter OF1 along the optical axis OA1 from the object side to the image side. The zoom lens 1 from the telephoto end to the wide-angle end of the zoom, the pitch of the second lens group G11 of the first lens group G12 D1 ₈₁₀ reduced by the distance D1 _810, D1 _1718, D1 ₁₉₂₀ changes the zoom lens can be adjusted to achieve a valid The focal length, which is varied as the zoom lens 1 is zoomed from the wide-angle end to the telephoto end, can be clearly seen in Figs. 1, 2, and 3.

In the present embodiment, the first lens group G11 has a negative refractive power, the second lens group G12 has a positive refractive power, and the third lens group G13 has a positive refractive power.

The first lens group G11 sequentially includes a first lens L11, a second lens L12, a third lens L13, and a fourth lens L14 from the object side to the image side along the optical axis OA1. The first lens L11 is a convex-concave lens, and the object side surface S11 is a convex surface, and both the object side surface S11 and the image side surface S12 are aspherical surfaces. The second lens L12 is a biconcave lens. The third lens L13 is a lenticular lens, the fourth lens L14 has a negative refractive power, and the refractive power of the object side surface S17 is greater than the refractive power of the image side surface S18, and both the object side surface S17 and the image side surface S18 are aspherical surfaces.

The second lens group G12 sequentially includes a fifth lens L15, a sixth lens L16, and a seventh lens L17 from the object side to the image side along the optical axis OA1. The fifth lens L15 has a positive refractive power for the cemented lens, and the fifth lens L15 is formed by joining a lens L151 and a lens L152. The sixth lens L16 has a positive refractive power, and both the object side surface S113 and the image side surface S114 are aspherical surfaces. The seventh lens L17 has a negative refractive power for the cemented lens, and the seventh lens L17 is formed by joining a lens L171 and a lens L172.

The third lens group G13 includes an eighth lens L18 having a positive refractive power and an object side surface S118 being an aspherical surface.

The aperture ST1 is located between the first lens group G11 and the second lens group G12, and the distance D1 ₉₁₀ between the aperture ST1 and the second lens group G12 is fixed. The filter OF1 is made of flat glass, and both the object side surface S120 and the image side surface S121 are flat.

In addition, in order to maintain good optical performance of the zoom lens of the present invention, the zoom lens 1 of the first embodiment is required to satisfy the following two conditions: 0.5<|β1 _2w |<0.9 (1)

Vd1 ₂ >80 (2)

Wherein β1 _2w is the lateral magnification of the second lens group at the wide-angle end, and Vd1 ₂ is the Abbe coefficient of the second lens.

With the design of the above lens and aperture ST1, the zoom lens 1 can achieve high zoom magnification and good optical performance.

Table 1 is a table of related parameters of the lenses of the zoom lens 1 of the first, second, and third figures at the wide-angle end, the middle end, and the telephoto end, respectively.

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.

The zoom lens 1 of the first embodiment can satisfy the requirements of the above conditions (1) to (2) with β1 _2w = -0.7441 and Vd1 ₂ = 81.50.

In addition, the optical performance of the zoom lens 1 of the present embodiment at the wide-angle end, the intermediate end, and the telephoto end can also be achieved, which can be obtained from the 4A to 4G, the 5A to 5G, and the 6A to 6G. see. 4A, 5A, and 6A are longitudinal aberration diagrams of the zoom lens 1 of the present embodiment at the wide-angle end, the intermediate end, and the telephoto end. 4B, 5B, and 6B are field Curvature diagrams of the zoom lens 1 of the present embodiment at the wide-angle end, the intermediate end, and the telephoto end. 4C, 5C, and 6C are distortion diagrams of the zoom lens 1 of the present embodiment at the wide-angle end, the intermediate end, and the telephoto end. 4D to 4F, 5D to 5F, and 6D to 6F are transverse light fans of the zoom lens 1 of the present embodiment at the wide-angle end, the middle end, and the telephoto end (Transverse Ray Fan). ) Figure. 4G, 5G, and 6G are lateral chromatic aberration diagrams of the zoom lens 1 of the present embodiment at the wide-angle end, the intermediate end, and the telephoto end.

As can be seen from FIG. 4A, when the zoom lens 1 of the present embodiment is at the wide angle end, The longitudinal aberration value for light having a wavelength of 0.436 μm, 0.546 μm, and 0.656 μm is between -0.04 mm and 0.04 mm. As can be seen from FIG. 4B, when the zoom lens 1 of the present embodiment is at the wide-angle end, the Tangential direction and the Sagittal direction field curvature are generated for the light having a wavelength of 0.436 μm, 0.546 μm, and 0.656 μm. Between -0.12mm and 0.20mm. It can be seen from Fig. 4C (the three lines in the figure are almost coincident, so that it appears that there is only one line). When the zoom lens 1 of the present embodiment is at the wide-angle end, the wavelengths are 0.436 μm, 0.546 μm, and 0.656 μm. The distortion caused by light is less than plus or minus 6.0%. As can be seen from the 4D, 4E, and 4F diagrams, when the zoom lens 1 of the present embodiment is at the wide-angle end, the light having a wavelength of 0.436 μm, 0.546 μm, and 0.656 μm is 0% image height and 80% respectively at the image height. The image height difference between the image height and the 100% image height is between -44.0 μm and 36.0 μm. As can be seen from FIG. 4G, when the zoom lens 1 of the present embodiment is at the wide-angle end, the wavelength is 0.587562 μm as a reference wavelength, and the light beams having wavelengths of 0.436 μm, 0.546 μm, and 0.656 μm are generated at different viewing field heights. The color difference is between -3.0 μm and 26.0 μm. It can be seen that the longitudinal aberration, field curvature, distortion, lateral aberration and lateral chromatic aberration of the zoom lens 1 of the present embodiment at the wide-angle end can be effectively corrected, thereby obtaining better optical performance.

As can be seen from FIG. 5A, when the zoom lens 1 of the embodiment is at the intermediate end, The longitudinal aberration value for light having a wavelength of 0.436 μm, 0.546 μm, and 0.656 μm is between -0.06 mm and 0.06 mm. It can be seen from Fig. 5B that when the zoom lens 1 of the present embodiment is at the intermediate end, the Tangential direction and the Sagittal direction field curvature are generated for the light having a wavelength of 0.436 μm, 0.546 μm, and 0.656 μm. Between -0.20mm and 0.04mm. It can be seen from Fig. 5C (the three lines in the figure are almost coincident, so that it seems that there is only one line). When the zoom lens 1 of the present embodiment is at the intermediate end, the wavelengths are 0.436 μm, 0.546 μm, and 0.656 μm. The distortion caused by light is less than plus or minus 0.5%. It can be seen from the 5D, 5E, and 5F diagrams that when the zoom lens 1 of the present embodiment is at the intermediate end, the light having a wavelength of 0.436 μm, 0.546 μm, and 0.656 μm is 0% image height and 80% respectively at the image height. The image height difference between the image height and the 100% image height is between -24.0 μm and 26.0 μm. It can be seen from FIG. 5G that when the zoom lens 1 of the present embodiment is at the intermediate end, the wavelength is 0.587562 μm as a reference wavelength, and the light beams having wavelengths of 0.436 μm, 0.546 μm, and 0.656 μm are generated at different viewing field heights. The color difference is between -1.0 μm and 20.0 μm. It can be seen that the longitudinal aberration, field curvature, distortion, lateral aberration and lateral chromatic aberration of the zoom lens 1 of the embodiment at the intermediate end can be effectively corrected, thereby obtaining Preferred optical properties.

As can be seen from FIG. 6A, when the zoom lens 1 of the embodiment is at the telephoto end, The longitudinal aberration value for light having a wavelength of 0.436 μm, 0.546 μm, and 0.656 μm is between -0.25 mm and 0.07 mm. It can be seen from FIG. 6B that when the zoom lens 1 of the present embodiment is at the telephoto end, the Tangential direction and the Sagittal direction field curvature are generated for the light having a wavelength of 0.436 μm, 0.546 μm, and 0.656 μm. Between -0.20mm and 0.22mm. It can be seen from Fig. 6C (the three lines in the figure are almost coincident, so that it seems that there is only one line). When the zoom lens 1 of the present embodiment is at the telephoto end, the wavelengths are 0.436 μm, 0.546 μm, and 0.656 μm. The distortion produced by light is less than plus or minus 1.5%. It can be seen from the 6D, 6E, and 6F diagrams that when the zoom lens 1 of the present embodiment is at the telephoto end, the light having a wavelength of 0.436 μm, 0.546 μm, and 0.656 μm is 0% image height and 80% respectively at the image height. The image height difference between the image height and the 100% image height is between -125.0 μm and 42.0 μm. It can be seen from FIG. 6G that when the zoom lens 1 of the present embodiment is at the telephoto end, the wavelength is 0.587562 μm as a reference wavelength, and the light beams having wavelengths of 0.436 μm, 0.546 μm, and 0.656 μm are generated at different viewing field heights. The color difference is between -1.0 μm and 16.0 μm. It can be seen that the longitudinal aberration, field curvature, distortion, lateral aberration and lateral chromatic aberration of the zoom lens 1 of the present embodiment at the telephoto end can be effectively corrected, thereby obtaining better optical performance.

Please refer to FIG. 7 , FIG. 8 and FIG. 9 . FIG. 7 is a schematic diagram of a lens arrangement and an optical path at a wide angle end according to a second embodiment of the zoom lens according to the present invention, and FIG. 8 is a diagram of a zoom lens according to the present invention. 2 is a schematic diagram of a lens arrangement and an optical path at the intermediate end, and FIG. 9 is a schematic diagram of a lens arrangement and an optical path at the telephoto end according to the second embodiment of the zoom lens of the present invention. The zoom lens 2 sequentially includes a first lens group G21, an aperture ST2, a second lens group G22, a third lens group G23, and a filter OF2 along the optical axis OA2 from the object side to the image side. The zoom lens 2 from the wide-angle end to the telephoto end of the zoom, the lens pitch of the second group G22 and G21 of the first lens group D2 ₈₁₀ reduced by the distance D2 _810, D2 _1718, D2 ₁₉₂₀ changes the zoom lens can be adjusted to achieve the effective 2 The focal length, which is varied as the zoom lens 2 is zoomed from the wide-angle end to the telephoto end, can be clearly seen in FIGS. 7 , 8 , and 9 .

In this embodiment, the first lens group G21 has a negative refractive power, and the second lens The group G22 has a positive refractive power, and the third lens group G23 has a positive refractive power.

The first lens group G21 includes a first order from the object side to the image side along the optical axis OA2 A lens L21, a second lens L22, a third lens L23 and a fourth lens L24. The first lens L21 is a convex-concave lens, and the object side surface S21 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 biconcave lens. The third lens L23 is a lenticular lens, the fourth lens L24 has a negative refractive power, and the refractive power of the object side surface S27 is greater than the refractive power of the image side surface S28, and both the object side surface S27 and the image side surface S28 are aspherical surfaces.

The second lens group G22 sequentially includes a fifth lens L25, a sixth lens L26, and a seventh lens L27 from the object side to the image side along the optical axis OA2. The fifth lens L25 has a positive refractive power for the cemented lens, and the fifth lens L25 is formed by joining a lens L251 and a lens L252. The sixth lens L26 has a positive refractive power, and both the object side surface S213 and the image side surface S214 are aspherical surfaces. The seventh lens L27 has a negative refractive power for the cemented lens, and the seventh lens L27 is formed by joining a lens L271 and a lens L272.

The third lens group G23 includes an eighth lens L28 having a positive refractive power and an object side surface S218 being an aspherical surface.

The aperture ST2 is located between the first lens group G21 and the second lens group G22, and the distance D2 ₉₁₀ between the aperture ST2 and the second lens group G22 is fixed. The filter OF2 is made of flat glass, and both the object side surface S220 and the image side surface S221 are flat.

In addition, in order to maintain good optical performance of the zoom lens of the present invention, the zoom lens 2 of the second embodiment needs to satisfy the following two conditions: 0.5<|β2 _2w |<0.9 (3)

Vd2 ₂ >80(4)

Wherein β2 _2w is the lateral magnification of the second lens group at the wide-angle end, and Vd2 ₂ is the Abbe coefficient of the second lens.

With the design of the above lens and aperture ST2, the zoom lens 2 can achieve high zoom magnification and good optical performance.

Table 3 is a table of related parameters of the lenses of the zoom lens 2 of Fig. 7, Fig. 8, and Fig. 9 at the wide angle end, the middle end, and the telephoto end, respectively.

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 zoom lens 2 of the second embodiment can satisfy the requirements of the above conditions (3) to (4) with β2 _2w = -0.8006 and Vd2 ₂ = 81.50.

In addition, the optical performance of the zoom lens 2 of the present embodiment at the wide-angle end, the intermediate end, and the telephoto end can also meet the requirements, such as longitudinal aberration, curvature of field, distortion, lateral aberration, and lateral chromatic aberration (the above illustration and the first implementation) The legends in the examples are similar, so the illustrations are omitted, and can be effectively corrected to obtain better optical performance.

Please refer to FIG. 10, FIG. 11 and FIG. 12, FIG. 10 is a schematic diagram of a lens arrangement and an optical path at a wide-angle end according to a third embodiment of the zoom lens according to the present invention, and FIG. 11 is a view of a zoom lens according to the present invention. 3 is a schematic diagram of a lens arrangement and an optical path at the intermediate end, and FIG. 12 is a schematic diagram of a lens configuration and an optical path at the telephoto end according to the third embodiment of the zoom lens of the present invention. The zoom lens 3 sequentially includes a first lens group G31, an aperture ST3, a second lens group G32, a third lens group G33, and a filter OF3 from the object side to the image side along the optical axis OA3. The zoom lens 3 by the wide-angle end to the telephoto zooming, the first lens group G31 and the second lens group G32 of the distance D3 ₈₁₀ reduced by the distance D3 _810, D3 _1718, D3 ₂₁₂₂ changes the zoom lens can be adjusted to achieve the effective 3 The focal length, which is varied as the zoom lens 3 is zoomed from the wide-angle end to the telephoto end, can be clearly seen in FIGS. 10, 11, and 12.

In the present embodiment, the first lens group G31 has a negative refractive power, the second lens group G32 has a positive refractive power, and the third lens group G33 has a positive refractive power.

The first lens group G31 sequentially includes a first lens L31, a second lens L32, a third lens L33, and a fourth lens L34 from the object side to the image side along the optical axis OA3. First through The mirror L31 is a convex-concave lens, and the object side surface S31 is a convex surface, and both the object side surface S31 and the image side surface S32 are aspherical surfaces. The second lens L32 is a biconcave lens. The third lens L33 is a lenticular lens, the fourth lens L34 has a negative refractive power, and the refractive power of the object side surface S37 is greater than the refractive power of the image side surface S38, and both the object side surface S37 and the image side surface S38 are aspherical surfaces.

The second lens group G32 sequentially includes a fifth lens L35, a sixth lens L36, and a seventh lens L37 from the object side to the image side along the optical axis OA3. The fifth lens L35 has a positive refractive power for the cemented lens, and the fifth lens L35 is formed by joining a lens L351 and a lens L352. The sixth lens L36 has a positive refractive power, and both the object side surface S313 and the image side surface S314 are aspherical surfaces. The seventh lens L37 has a negative refractive power for the cemented lens, and the seventh lens L37 is formed by joining a lens L371 and a lens L372.

The third lens group G33 includes an eighth lens L38 and a ninth lens L39. The eighth lens L38 has a positive refractive power, and the object side surface S318 is an aspherical surface. The object side surface S320 and the image side surface S321 of the ninth lens L39 are both planar.

The aperture ST3 is located between the first lens group G31 and the second lens group G32, and the distance D3 ₉₁₀ between the aperture ST3 and the second lens group G32 is fixed. The filter OF3 is made of flat glass, and both the object side surface S320 and the image side surface S321 are flat.

In addition, in order to maintain good optical performance of the zoom lens of the present invention, the zoom lens 3 of the third embodiment is required to satisfy the following two conditions: 0.5<|β3 _2w |<0.9 (5)

Vd3 ₂ >80 (6)

Wherein β3 _2w is the lateral magnification of the second lens group at the wide-angle end, and Vd3 ₂ is the Abbe coefficient of the second lens.

With the design of the above lens and aperture ST3, the zoom lens 3 can achieve high zoom magnification and good optical performance.

Table 5 is a table of related parameters of the lenses of the zoom lens 3 of the 10th, 11th, and 12th drawings at the wide-angle end, the middle end, and the telephoto end, respectively.

The aspherical surface depression z of each lens in Table 5 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 6 is the relevant parameter table of the aspherical surface of each lens in Table 5, where k is the conic coefficient (Conic Constant) and A~E is the aspherical coefficient.

The zoom lens 3 of the third embodiment can satisfy the requirements of the above conditions (5) to (6) with β3 _2w = -0.7657 and Vd3 ₂ = 81.50.

In addition, the optical performance of the zoom lens 3 of the present embodiment at the wide-angle end, the intermediate end, and the telephoto end can also meet the requirements, such as longitudinal aberration, curvature of field, distortion, lateral aberration, and lateral chromatic aberration (the above illustration and the first implementation) The legends in the examples are similar, so the illustrations are omitted, and can be effectively corrected to obtain better optical performance.

Although the present invention has been described above in terms of the preferred embodiments, it is not intended to limit the invention, and the invention may be modified and modified without departing from the spirit and scope of the invention. The scope of the invention is defined by the scope of the appended claims.

1‧‧‧ zoom lens

G11‧‧‧First lens group

L11‧‧‧ first lens

L12‧‧‧ second lens

L13‧‧‧ third lens

L14‧‧‧4th lens

G12‧‧‧Second lens group

L15‧‧‧ fifth lens

L16‧‧‧ sixth lens

L17‧‧‧ seventh lens

L151‧‧ lens

L152‧‧ lens

L171‧‧ lens

L172‧‧ lens

G13‧‧‧ third lens group

L18‧‧‧ eighth lens

OA1‧‧‧ optical axis

ST1‧‧‧ aperture

OF1‧‧‧Filter

IMA1‧‧‧ imaging surface

S11, S12, S13, S14, S15, S16, S17‧‧

S18, S19, S110, S111, S112, S113‧‧‧

S114, S115, S116, S117, S118, S119‧‧

S120, S121‧‧‧

D1 ₈₉ , D1 ₉₁₀ , D1 ₈₁₀ , D1 ₁₇₁₈ , D1 ₁₉₂₀ ‧‧‧ spacing

Claims (12)

A zoom lens sequentially includes, from the object side to the image side along the optical axis, a first lens group having a negative refractive power, the first lens group along the optical axis from the object side to the The image side includes a first lens, a second lens, a third lens and a fourth lens. The first lens is a convex-concave lens, and the convex surface of the first lens faces the object side, and the fourth lens object The lateral refractive power is greater than the refractive power of the image side, the fourth lens has a negative refractive power; a second lens group having a positive refractive power, the second lens group along the optical axis from the object side to the image The side sequence includes a fifth lens, a sixth lens, and a seventh lens, the fifth lens has a positive refractive power, the sixth lens has a positive refractive power, the seventh lens has a negative refractive power, and a third lens group, The third lens group has a positive refractive power. The zoom lens of claim 1, wherein the second lens is a biconcave lens, and the third lens is a lenticular lens. The zoom lens according to claim 1, wherein the second lens group satisfies the following condition: 0.5 < | β _2w | < 0.9, wherein β _2w is a lateral magnification of the second lens group at the wide-angle end. The zoom lens of claim 1, wherein the second lens satisfies the following condition: Vd ₂ >80, wherein Vd ₂ is an Abbe coefficient of the second lens. The zoom lens of claim 4, wherein the first lens group moves along the optical axis direction when the zoom lens is in focus. The zoom lens according to claim 4, wherein the fifth lens is a cemented lens, the sixth lens is a single lens, and the seventh lens is a cemented lens. The zoom lens according to claim 6, wherein the first lens group moves in the optical axis direction when the zoom lens is in focus. The zoom lens according to claim 1, wherein the fifth lens is a cemented lens, the sixth lens is a single lens, and the seventh lens is a cemented lens. The zoom lens of claim 8, wherein the first lens group moves along the optical axis direction when the zoom lens is in focus. The zoom lens according to claim 1, wherein the first lens group moves in the optical axis direction when the zoom lens is in focus. The zoom lens of claim 1, wherein the distance between the first lens group and the second lens group is reduced when the zoom lens is zoomed from the wide-angle end to the telephoto end. The zoom lens of claim 1, further comprising an aperture disposed between the first lens group and the second lens group.