TWI461776B - Wide angle focus lens - Google Patents

Description

Wide-angle zoom lens

The present invention relates to a zoom lens, and more particularly to a wide-angle zoom lens.

One of the most important parameters of the zoom lens is the zoom ratio. However, in the conventional zoom lens, when the zoom ratio is required to be high, the aberration at the telephoto end is difficult to correct, and when the angle of view is large, the wide-angle end aberration is difficult to correct. Therefore, in the mirror design process, it is difficult to obtain a lens having a high imaging quality while satisfying a high zoom ratio and a wide viewing angle.

In view of this, it is necessary to provide a wide-angle zoom lens with high image quality.

A wide-angle zoom lens comprising, in order from its object side to the image side direction, a first lens group of positive power, a second lens group of negative power, a third lens group of positive power, and a wide optical lens a fourth lens group of positive power; the first lens group, the second lens group, the third lens group, and the fourth lens group are movable along an optical axis during zooming; the wide-angle zoom lens satisfies the conditional expression 1.6< F3/fw<2.1, where f3 is the effective focal length of the third lens group, and fw is the effective focal length of the wide-angle zoom lens in the wide-angle end state.

Compared with the prior art, the wide-angle zoom lens of the present invention has high imaging quality while satisfying a high zoom ratio and a wide viewing angle.

100‧‧‧ wide-angle zoom lens

10‧‧‧First lens group

11‧‧‧First lens

12‧‧‧second lens

20‧‧‧second lens group

21‧‧‧ third lens

22‧‧‧Fourth lens

23‧‧‧ fifth lens

30‧‧‧third lens group

31‧‧‧ sixth lens

32‧‧‧ seventh lens

33‧‧‧ eighth lens

34‧‧‧ ninth lens

40‧‧‧Fourth lens group

50‧‧‧ aperture

60‧‧‧Image sensor

70‧‧‧Filter

FIG. 1 is a schematic structural view of a wide-angle zoom lens according to a first embodiment of the present invention.

2 is an aberration diagram of the wide-angle zoom lens of FIG. 1 in a wide-angle state.

3 is a field curvature diagram of the wide-angle zoom lens of FIG. 1 in a wide-angle state.

4 is a distortion diagram of the wide-angle zoom lens of FIG. 1 in a wide-angle state.

FIG. 5 is an aberration diagram of the wide-angle zoom lens of FIG. 1 in a telephoto state. FIG.

FIG. 6 is a field curvature diagram of the wide-angle zoom lens of FIG. 1 in a telephoto state.

FIG. 7 is a distortion diagram of the wide-angle zoom lens of FIG. 1 in a telephoto state.

FIG. 8 is a schematic structural diagram of a wide-angle zoom lens according to a second embodiment of the present invention.

FIG. 9 is an aberration diagram of the wide-angle zoom lens of FIG. 2 in a wide-angle state. FIG.

Fig. 10 is a field curvature diagram of the wide-angle zoom lens of Fig. 2 in a wide-angle state.

Fig. 11 is a distortion diagram of the wide-angle zoom lens of Fig. 2 in a wide-angle state.

FIG. 12 is an aberration diagram of the wide-angle zoom lens of FIG. 2 in a telephoto state. FIG.

FIG. 13 is a field curvature diagram of the wide-angle zoom lens of FIG. 2 in a telephoto state.

FIG. 14 is a distortion diagram of the wide-angle zoom lens of FIG. 2 in a telephoto state.

The technical solution will be further described in detail below with reference to the accompanying drawings and embodiments.

Please refer to FIG. 1 , which is a wide-angle zoom lens 100 according to a first embodiment of the present invention, which includes a first lens group 10 having positive refractive power and a negative optical power from the object side to the image side. a second lens group 20, a third lens group 30 having positive power a fourth lens group 40 having positive refractive power, an aperture 50 between the second lens group 20 and the third lens group 30, an image sensor 60 on the image side of the fourth lens group 40, and A filter 70 is disposed between the fourth lens group 40 and the image sensor 60. The filter 70 is attached to the surface of the image sensor 60. When the wide-angle zoom lens 100 performs zooming, the first lens group 10, the second lens group 20, the third lens group 30, and the fourth lens group 40 are all moved along the optical axis to compensate for the zoom process and the object distance change. The resulting image plane position changes.

The first lens group 10 includes, in order from the object side to the image side, a first lens 11 having a negative refractive power and a second lens 12 having a positive refractive power. The first lens 11 and the second lens 12 are both spherical lenses, and the first lens 11 and the second lens 12 are glued together to form a cemented lens. The first lens 11 is of a crescent type and includes a first surface that protrudes toward the object side and a second surface that is concave toward the image side. The second lens 12 is of a crescent type and includes a third surface that protrudes toward the object side and a fourth surface that is concave toward the image side.

The second lens group 20 includes, in order from the object side to the image side, a third lens 21 having a negative refractive power, a fourth lens 22 having a negative refractive power, and a fifth lens 23 having a positive refractive power. The third lens 21, the fourth lens 22, and the fifth lens 23 are both spherical lenses. The third lens 21 is of a crescent type and includes a fifth surface that is convex toward the object side and a sixth surface that is concave toward the image side. The fourth lens 22 is a concave lens including a seventh surface concave toward the object side and an eighth surface concave toward the image side. The fifth lens 23 is a convex lens including a ninth surface that is convex toward the object side and a tenth surface that is convex toward the image side.

The third lens group 30 includes, in order from the object side to the image side, a sixth lens 31 having a positive power, a seventh lens 32 having a positive power, and an eighth having a negative power. The lens 33 and a ninth lens 34 having positive power. The sixth lens 31 is an aspherical lens, and the seventh lens 32, the eighth lens 33, and the ninth lens 34 are both spherical lenses. The sixth lens 31 is a convex lens including an eleventh surface that is convex toward the object side and a twelfth surface that is convex toward the image side. The seventh lens 32 is of a crescent type and includes a thirteenth surface convex toward the object side and a fourteenth surface concave toward the image side. The eighth lens 33 is of a crescent type and includes a fifteenth surface that is convex toward the object side and a sixteenth surface that is concave toward the image side. The ninth lens 34 is of a crescent type and includes a seventeenth surface concave toward the object side and an eighteenth surface convex toward the image side.

The fourth lens group 40 is a tenth lens having positive power. The tenth lens is a spherical lens. The tenth lens is a convex lens including a nineteenth surface that is convex toward the object side and a twentieth surface that is convex toward the image side.

The filter 70 has a flat shape and includes a twenty-first surface facing the object side and a second surface facing the image side.

The wide-angle zoom lens 100 satisfies the following conditional formula: (1) 1.6 < f3 / fw < 2.1; wherein f3 is the effective focal length of the third lens group, and fw is the effective focal length of the wide-angle zoom lens in the wide-angle end state.

The conditional expression (1) makes the mid-focus end beam of the wide-angle zoom lens 100 smaller, which causes the off-axis beam to generate a smaller coma, enhances the peripheral resolution, and makes the astigmatism and axial chromatic aberration at the telephoto end smaller.

Preferably, the wide-angle zoom lens 100 also satisfies the following conditions: (2) 1.55 < V2 / V1 < 1.95; wherein V1 is the Abbe number of the d ray of the first lens 11, and V2 is the Abbe number of the d ray of the second lens 12.

The conditional expression (2) corrects the axial chromatic aberration at the wide-angle end of the wide-angle zoom lens 100, and the lateral chromatic aberration at the telephoto end is corrected.

Preferably, the wide-angle zoom lens 100 further satisfies the following condition: (3) 1.00 < V7 / V8 < 2.2; wherein V7 is the Abbe number of the d ray of the seventh lens 32, and V8 is the eighth lens 33 Abbe number of d rays.

The conditional expression (3) allows a good balance between the wide-angle end of the wide-angle zoom lens 100 and the lateral chromatic aberration at the telephoto end.

In the first embodiment, each optical element of the wide-angle zoom lens 100 satisfies the conditions of Tables 1 to 3, where f3 = 8.8 mm; fw = 4.589 mm; f3/fw = 1.918; V1 = 29.1; V2 = 47.5; /V1=1.632; V7=25.5; V8=21.2; V8/V7=0.83.

The meanings of the parameters in Tables 1 to 3 are as follows: R: radius of curvature of the surface; D: distance from the surface to the back surface on the optical axis; Nd: refractive index of the lens; Vd: Abbe's coefficient of the lens; : effective focal length of the wide-angle zoom lens 100; D3: distance from the fourth surface to the fifth surface along the optical axis; D9: distance from the tenth surface to the eleventh surface along the optical axis; D17: from the eighteenth surface to the nineteenth surface along the optical axis The distance on the upper side; D19: the distance from the twentieth surface to the twenty-first surface along the optical axis.

Table 2

Among them, the aspherical surface type is as follows:

among them, For the height from the optical axis to the lens surface, k is the quadric coefficient, A _i is the aspherical surface coefficient of the i-th order, and c is the curvature of the center of the mirror surface.

The wide-angle zoom lens 100 satisfying Tables 1 to 3 satisfies the conditions of Table 4, and in Table 4, 2 ω is the angle of view of the wide-angle zoom lens 100; FNo is the number of apertures of the wide-angle zoom lens 100.

Table 4

The aberration, curvature of field, and distortion of the wide-angle zoom lens 100 in the wide-angle state are as shown in FIGS. 2 to 4, respectively. The aberration control in Fig. 2 is in the range of (-0.20 mm, 0.20 mm). The meridional curvature values and the sagittal field curvature values in Fig. 3 are both controlled within the range of (-0.20 mm, 0.20 mm). The distortion rate in Fig. 4 is controlled within the range of (-20%, 0). It can be seen that the wide-angle zoom lens 100 can be well corrected for aberration, field curvature, and distortion in the wide-angle state.

The aberration, curvature of field, and distortion of the wide-angle zoom lens 100 in the telephoto state are as shown in FIGS. 5 to 7, respectively. The aberration control in Fig. 5 is in the range of (-0.20 mm, 0.20 mm). The Meridian field value and the sagittal field curvature value in Fig. 6 are both controlled within the range of (-0.20 mm, 0.20 mm). The distortion rate in Fig. 7 is controlled within the range of (0, 5%). It can be seen that the wide-angle zoom lens 100 can be well corrected for aberration, field curvature, and distortion in the telephoto state.

Please refer to FIG. 8, which is a wide-angle zoom system 200a according to a second embodiment of the present invention, which includes a wide-angle zoom lens 100a. The wide-angle zoom lens 100a provided by the second embodiment is different from the wide-angle zoom lens 100 provided by the first embodiment in that the fifth lens 23a has a crescent shape, and the ninth surface faces the object side. Protruding, the tenth surface is concave toward the image side; the seventh lens 32a is a convex lens, the thirteenth surface is convex toward the object side, and the fourteenth surface is convex toward the image side; The eight lens 33a is a concave lens, the fifteenth surface is concave toward the object side, and the sixteenth surface is concave toward the image side.

In the second embodiment, each optical element of the wide-angle zoom lens 100a satisfies the conditions of Tables 5 to 7, wherein f3 = 7.99 mm; fw = 4.59 mm; f3/fw = 1.741; V1 = 25.5. ; V2 = 47.5; V2 / V1 = 1.863; V7 = 42.7; V8 = 21.2; V8 / V7 = 0.49.

The meanings of the parameters in Tables 5 to 7 are as follows: R: radius of curvature of the surface; D: distance from the surface to the back surface on the optical axis; Nd: refractive index of the lens; Vd: Abbe's coefficient of the lens; : effective focal length of the wide-angle zoom lens 100a; D3: distance from the fourth surface to the fifth surface along the optical axis; D9: distance from the tenth surface to the eleventh surface along the optical axis; D17: from the tenth The distance from the eight surface to the nineteenth surface along the optical axis; D19: the distance from the twentieth surface to the twenty-first surface along the optical axis.

table 5

Table 7

Among them, the aspherical surface type is as follows:

among them, For the height from the optical axis to the lens surface, k is the quadric coefficient, A _i is the aspherical surface coefficient of the i-th order, and c is the curvature of the center of the mirror surface.

The wide-angle zoom lens 100a that satisfies Tables 5 to 7 satisfies the conditions of Table 8. In Table 8, 2 ω is the angle of view of the wide-angle zoom lens 100a; FNo is the number of apertures of the wide-angle zoom lens 100a.

The aberration, curvature of field, and distortion of the wide-angle zoom lens 100a in the wide-angle state are as shown in FIGS. 9 to 11, respectively. The aberration control in Fig. 9 is in the range of (-0.20 mm, 0.20 mm). Figure The meridional field curvature value and the sagittal field curvature value in 10 are both controlled within the range of (-0.20 mm, 0.20 mm). The distortion rate in Fig. 11 is controlled within the range of (-20%, 0). It can be seen that the wide-angle zoom lens 100a can be well corrected for aberration, field curvature, and distortion in the wide-angle state.

The aberration, curvature of field, and distortion of the wide-angle zoom lens 100a in the telephoto state are as shown in FIGS. 12 to 14, respectively. The aberration control in Fig. 12 is in the range of (-0.20 mm, 0.20 mm). The Meridian field value and the sagittal field curvature value in Fig. 13 are both controlled within the range of (-0.20 mm, 0.20 mm). The distortion rate in Fig. 14 is controlled within the range of (0, 5%). It can be seen that the aberration, curvature of field, and distortion of the wide-angle zoom lens 100a in the telephoto state can be well corrected.

Among them, the wavelength of the F line in FIG. 2-7 and FIG. 9-14 is 486 nm, the wavelength of the d line is 587 nm, and the wavelength of the C line is 656 nm.

The wide-angle zoom lens and the wide-angle zoom system of the present invention have high imaging quality while satisfying a high zoom ratio and a wide viewing angle.

In summary, the present invention has indeed met the requirements of the invention patent, and has filed a patent application according to law. However, the above description is only a preferred embodiment of the present invention, and it is not possible to limit the scope of the patent application of the present invention. Equivalent modifications or variations made by persons skilled in the art in light of the spirit of the invention are intended to be included within the scope of the following claims.

100‧‧‧ wide-angle zoom lens

10‧‧‧First lens group

11‧‧‧First lens

12‧‧‧second lens

20‧‧‧second lens group

21‧‧‧ third lens

22‧‧‧Fourth lens

23‧‧‧ fifth lens

30‧‧‧third lens group

31‧‧‧ sixth lens

32‧‧‧ seventh lens

33‧‧‧ eighth lens

34‧‧‧ ninth lens

40‧‧‧Fourth lens group

50‧‧‧ aperture

60‧‧‧Image sensor

70‧‧‧Filter

Claims (10)

A wide-angle zoom lens comprising, in order from its object side to the image side direction, a first lens group of positive power, a second lens group of negative power, a third lens group of positive power, and a wide optical lens a fourth lens group of positive power; the first lens group, the second lens group, the third lens group, and the fourth lens group are movable along an optical axis during zooming; the wide-angle zoom lens satisfies the conditional expression 1.6< F3/fw<1.918, where f3 is the effective focal length of the third lens group, and fw is the effective focal length of the wide-angle zoom lens in the wide-angle end state. The wide-angle zoom lens according to claim 1, wherein the first lens group includes, in order from the object side to the image side, a first lens having a negative refractive power and a second lens having a positive refractive power. The wide-angle zoom lens according to claim 2, wherein the wide-angle zoom lens further satisfies the following conditional expression: 1.55 < V2 / V1 < 1.95; wherein V1 is an Abbe number of the d ray of the first lens, and V2 is The Abbe number of the d ray of the second lens. The wide-angle zoom lens of claim 2, wherein the first lens and the second lens are cemented lenses. The wide-angle zoom lens of claim 1, wherein the second lens group includes, in order from the object side to the image side, a third lens having a negative refractive power, a fourth lens having a negative refractive power, and a first lens. A fifth lens having positive power. The wide-angle zoom lens according to claim 1, wherein the third lens group includes, in order from the object side to the image side, a sixth lens having a positive power, a seventh lens having a positive power, and a negative lens. An eighth lens of power and a ninth lens having positive power. The wide-angle zoom lens according to claim 6, wherein the wide-angle zoom lens further satisfies the following conditions Formula: 1.00 < V7 / V8 < 2.2; wherein V7 is the Abbe number of the d ray of the seventh lens, and V8 is the Abbe number of the d ray of the eighth lens. The wide-angle zoom lens of claim 6, wherein the seventh lens and the eighth lens are cemented lenses. The wide-angle zoom lens of claim 6, wherein the sixth lens is an aspherical lens. The wide-angle zoom lens of claim 1, wherein the wide-angle zoom lens further includes an image sensor located on an image side of the fourth lens group.