TW201435385A - Zoom lens - Google Patents

Abstract

A zoom lens including a first lens group and a second lens group arranged in sequence from a magnified side to a reduced side is provided. The first lens group has a negative refractive power, and includes a first lens, a second lens, a third lens, and a fourth lens arranged in sequence from the magnified side to the reduced side. Refractive powers of the first lens, the second lens, the third lens, and the fourth lens are respectively negative, negative, negative, and positive. The second lens group has a positive refractive power, and includes a fifth lens, a sixth lens, a seventh lens, an eighth lens, and a ninth lens arranged in sequence from the magnified side to the reduced side. Refractive powers of the fifth lens, the sixth lens, the seventh lens, the eighth lens, and the ninth lens are respectively positive, negative, positive, negative, and positive.

Description

Zoom lens

The present invention relates to an optical lens, and more particularly to a zoom lens.

With the advancement of optoelectronic technology, image sensing devices (such as cameras, cameras, etc.) have been widely used in various fields of daily life, or in the production line of factories, to replace the original human or artificial things. In this way, human beings can have more time and manpower to do more important things. On the other hand, the use of image sensing devices allows people to notice places that are not easily noticeable by the human eye, or to achieve effective monitoring effects in the absence of people.

In the image sensing device, in addition to the image sensor (such as a charge coupled device (CCD) or a complementary metal oxide semiconductor sensor (CMOS sensor), etc.) In addition to the decisive influence of the detected image quality, the quality of the optical lens is also key. Therefore, how to properly design the lens to achieve good image quality has always been the focus of lens designers.

U.S. Patent Nos. 5,155,629, 5,239,402, 7,932,075, A zoom lens is proposed in No. 7,555,839, No. 6,793,183, No. 7,944,620, No. 7,182,220, No. 6,917,477, and No. 6,809,882. Further, a projection lens is proposed in U.S. Patent No. 7,075,719.

The invention provides a zoom lens, which has the advantages of small volume, wide viewing angle, high resolution, large aperture and good infrared correction.

Other objects and advantages of the present invention will become apparent from the technical features disclosed herein.

In order to achieve one or a part or all of the above or other purposes, an embodiment of the present invention provides a zoom lens for being disposed between an enlarged side and a reduced side. The zoom lens includes a first lens group and a second lens group. The first lens group is disposed between the magnification side and the reduction side and has a negative power. The first lens group includes a first lens, a second lens, a third lens, and a fourth lens which are sequentially arranged from the magnification side to the reduction side, and the diopter of the first lens, the second lens, the third lens, and the fourth lens are The order is negative, negative, negative and positive. The second lens group is disposed between the first lens group and the reduction side and has a positive refractive power. The second lens group includes a fifth lens, a sixth lens, a seventh lens, an eighth lens, and a ninth lens which are sequentially arranged from the magnification side to the reduction side, and the fifth lens, the sixth lens, the seventh lens, and the eighth lens The diopter of the lens and the ninth lens are positive, negative, positive, negative and positive. The zoom lens conforms to -2.8<f1/fw<-2.3 and 0.6<| f1/f2 |<0.9, where f1 is the effective focal length (EFL) of the first lens group, and f2 is the effective focal length of the second lens group. Distance, and fw is the effective focal length of the zoom lens at the wide-angle end.

Based on the above, the zoom lens according to the embodiment of the present invention has a lens combination in which the diopter is negative, negative, negative, positive, positive, negative, positive, negative, and positive from the magnification side to the reduction side, and conforms to -2.8<f1. /fw<-2.3 and 0.6<| f1/f2 |<0.9, therefore, the embodiment of the present invention has no lens and wide viewing angle and good image quality.

The above described features and advantages of the invention will be apparent from the following description.

50‧‧‧ glass cover

60‧‧‧Image sensor

70‧‧‧Infrared light cut-off filter

80‧‧‧Transparent substrate

100, 100a‧‧‧ zoom lens

110‧‧‧First lens group

111‧‧‧First lens

112‧‧‧second lens

113‧‧‧ third lens

114‧‧‧Fourth lens

115, 126‧‧ ‧ double cemented lens

120, 120a‧‧‧second lens group

121‧‧‧ fifth lens

122‧‧‧ sixth lens

123‧‧‧ seventh lens

124, 124a‧‧‧ eighth lens

125, 125a‧‧‧ ninth lens

130‧‧‧ aperture diaphragm

A‧‧‧ optical axis

S1~S18‧‧‧ surface

1A to FIG. 1C are schematic diagrams showing the structure of a zoom lens at a wide angle end, an intermediate position, and a telephoto end, respectively, according to an embodiment of the present invention.

2A to 2C are optical simulation data diagrams of the zoom lens of Fig. 1A at the wide-angle end.

3A to 3C are optical simulation data diagrams of the zoom lens of Fig. 1B in an intermediate position.

4A to 4C are optical simulation data diagrams of the zoom lens of Fig. 1C at the telephoto end.

5A to 5C are schematic diagrams showing the structure of a zoom lens at a wide angle end, an intermediate position, and a telephoto end, respectively, according to another embodiment of the present invention.

6A to 6C are optical simulation data diagrams of the zoom lens of Fig. 5A at the wide angle end.

7A to 7C are optical simulation data diagrams of the zoom lens of Fig. 5B in an intermediate position.

8A to 8C are optical simulation data diagrams of the zoom lens of Fig. 5C at the telephoto end.

The above and other technical contents, features and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments. The directional terms mentioned in the following embodiments, such as up, down, left, right, front or back, etc., are only directions referring to the additional drawings. Therefore, the directional terminology used is for the purpose of illustration and not limitation.

1A to FIG. 1C are schematic diagrams showing the structure of a zoom lens at a wide angle end, an intermediate position, and a telephoto end, respectively, according to an embodiment of the present invention. Referring to FIG. 1A to FIG. 1C , the zoom lens 100 of the embodiment is disposed between the magnification side and the reduction side. The zoom lens 100 includes a first lens group 110 and a second lens group 120. The first lens group 110 is disposed between the magnification side and the reduction side and has a negative refracting power. The first lens group 110 includes a first lens 111, a second lens 112, a third lens 113, and a fourth lens 114 which are sequentially arranged from the magnification side to the reduction side, and the first lens 111, the second lens 112, and the third lens The diopter of 113 and fourth lens 114 are negative, negative, negative, and positive in sequence. The second lens group 120 is disposed between the first lens group 110 and the reduction side and has a positive refractive power. The second lens group 120 includes a fifth lens 121, a sixth lens 122, a seventh lens 123, an eighth lens 124, and a ninth lens which are sequentially arranged from the magnification side to the reduction side. The mirror 125, and the refracting power of the fifth lens 121, the sixth lens 122, the seventh lens 123, the eighth lens 124, and the ninth lens 125 are positive, negative, positive, negative, and positive.

In the present embodiment, the zoom lens 100 conforms to -2.8<f1/fw<-2.3 and 0.6<| f1/f2 |<0.9, where f1 is the effective focal length of the first lens group 110, and f2 is the second lens group 120. The effective focal length, and fw is the effective focal length of the zoom lens 100 at the wide-angle end.

In this embodiment, the first lens 111, the second lens 112, the third lens 113, and the fourth lens 114 are all spherical lenses, and the fifth lens 121, the sixth lens 122, and the seventh lens 123, At least two of the eighth lens 124 and the ninth lens 125 are aspheric lenses. Specifically, in the embodiment, the fifth lens 121 is, for example, an aspherical lens, and the ninth lens 125 is, for example, an aspherical lens, and the sixth lens 122, the seventh lens 123, and the eighth lens 124 are, for example, spherical lenses. .

In the embodiment, the zoom lens 100 further includes an aperture stop 130 disposed between the first lens group 110 and the second lens group 120. In the embodiment, the second lens group 120 is a zoom group, and the first lens group 110 is a focus group. In addition, in the present embodiment, when the zoom lens 100 is changed from the wide-angle end to the telephoto end, the position of the aperture stop 130 remains unchanged with respect to the reduction side, and the first lens group 110 and the second lens group 120 are directed to the aperture light. The crucible 130 is close, for example, from the state of FIG. 1A to the state of FIG. 1B, and then changes to the state of FIG. 1C.

In the embodiment, the third lens 113 and the fourth lens 114 form a double cemented lens 115, and the sixth lens 122 and the seventh lens 123 forms a double cemented lens 126. Further, in the present embodiment, the first lens 111 is, for example, a convex concave lens having a convex surface toward the magnification side, the second lens 112 is, for example, a biconcave lens, and the third lens 113 is, for example, convex toward the magnification side. For the convex-concave lens, the fourth lens 114 is, for example, a concave convex lens having a convex surface facing the magnification side, the fifth lens 121 is, for example, a biconvex lens, and the sixth lens 122 is, for example, a convex-concave lens having a convex surface facing the magnification side. The seventh lens 123 is, for example, a lenticular lens, and the eighth lens 124 is, for example, a convex-concave lens whose convex surface faces the magnification side, and the ninth lens 125 is, for example, a lenticular lens. In addition, in the embodiment, the image sensor 60 may be disposed on the reduction side, and the scene on the magnification side may be imaged on the image sensor 60 by the zoom lens 100. The image sensor 60 is, for example, a digital micromirror element or a complementary MOS sensing element. When the zoom lens 100 is zoomed, the position of the aperture stop 130 remains unchanged with respect to the position of the image sensor 60.

The zoom lens 100 of the present embodiment adopts a lens combination in which the dioptric power is negative, negative, negative, positive, positive, negative, positive, negative, and positive from the magnification side to the reduction side, and the first lens group 110 and the second lens group 120 are used. The diopter of the present embodiment is negative and positive, and the first lens group 110 and the second lens group 120 are both moved relative to the reduction side (ie, moved relative to the aperture stop 130) during zooming, so the zoom lens 100 of the embodiment can be small. The effect is that the picture has no vignetting and wide viewing angle. For example, the zoom lens 100 of the present embodiment can make the field of view (FOV) in the diagonal direction of the image sensor 60 as high as 143.2 degrees. In addition, the zoom lens 100 of the present embodiment can achieve a resolution of three megapixels. In addition, the zoom lens 100 of the present embodiment A part of the lens (for example, the seventh lens 123) may be made of a low-dispersion glass material to enhance the confocal effect of visible light and infrared light. In other words, the image sensing device using the zoom lens 100 can detect a clear image with good focus when detecting visible light images during the day and infrared light images during the night. Furthermore, the zoom lens 100 of the present embodiment can have a large aperture. In an embodiment, the aperture value (f-number) of the zoom lens can be as small as 1.4. The zoom lens 100 of the present embodiment is adapted to be matched with a larger size image sensor 60. However, when the zoom lens 100 of the present embodiment is matched with the smaller size image sensor 60, a good viewing range can still be provided.

One embodiment of the zoom lens 100 will be described below. It should be noted that the data listed in Tables 1, 2 and 3 below are not intended to limit the invention, and any person having ordinary skill in the art after referring to the present invention may The setting is made as appropriate, but it should still fall within the scope of the invention.

In Table 1, the pitch refers to the linear distance between two adjacent surfaces on the optical axis A. For example, the distance between the surfaces S1, that is, the surface S1 to the surface S2 is between the optical axis A. Straight line distance. For the thickness, refractive index, and Abbe number of each lens in the remark column, refer to the values corresponding to the pitch, refractive index, and Abbe number in the same column. Further, in Table 1, the surfaces S1, S2 are the two surfaces of the first lens 111, the surfaces S3, S4 are the two surfaces of the second lens 112, the surface S5 is the surface of the third lens 113 facing the magnification side, and the surface S6 is The surface of the third lens 113 connected to the fourth lens 114, and the surface S7 is the surface of the fourth lens 114 facing the reduction side. The surface S8 is a position of an infrared cut filter 70 (for example, an infrared cut film), and the surface S9 is a position of the aperture stop 130, wherein the transparent substrate 80 is used to carry the infrared cut filter. The optical device 70 has a surface S8 which is a surface facing the magnification side of the light-transmitting substrate 80, and a surface S9 which is a surface of the light-transmitting substrate 80 facing the reduction side. The surfaces S10 and S11 are the two surfaces of the fifth lens 121, the surface S12 is the surface facing the magnification side of the sixth lens 122, the surface S13 is the surface of the sixth lens 122 connected to the seventh lens 123, and the surface S14 is the seventh lens. The surface of 123 faces the side of the reduction side. The surfaces S15 and S16 are both surfaces of the eighth lens 124, and the surfaces S17 and S18 are both surfaces of the ninth lens 125. A cover glass 50 may be disposed between the surface S18 and the image sensor 60 to protect the image sensor 60. The pitch filled in the row of the surface S18 is the pitch of the surface S18 to the image sensor 60.

In addition, Table 2 lists the effective focal length, aperture value (F/#), field of view angle, and variable pitches d1, d2, and d3 of the zoom lens 100 at the wide-angle end, the middle position, and the telephoto end.

The above-mentioned surfaces S10, S11, S17 and S18 are even-order aspheric surfaces, and they can be expressed by the following formula:

Where Z is the offset (sag) in the direction of the optical axis A, and c is the reciprocal of the radius of the osculating sphere, that is, the radius of curvature near the optical axis A (see S10, S11, S17 in Table 1). And the reciprocal of the radius of curvature of S18. k is a quadric coefficient (conic), r is an aspherical height, that is, a height from the center of the lens toward the edge of the lens, and A ₂ , A ₄ , A ₆ , A _{8 ,} and A _{10 are} aspheric coefficients. In the present embodiment, the coefficient A ₂ is zero. Listed below in Table 3 are the aspheric parameter values for surfaces S10, S11, S17, and S18.

2A to 2C are optical simulation data diagrams of the zoom lens of FIG. 1A at the wide-angle end, and FIGS. 3A to 3C are optical simulation data diagrams of the zoom lens of FIG. 1B at an intermediate position, and FIGS. 4A to 4C are diagrams. Optical analog data of the 1C zoom lens at the telephoto end. Please refer to FIG. 2A to FIG. 4C , wherein FIG. 2A , FIG. 3A and FIG. 4A are simulation data diagrams of longitudinal aberrations simulated by a wavelength of 588 nm, wherein the pupil radius of FIG. 2A is 1.0135 mm, the pupil radius of Figure 3A is 1.4449 mm, and the pupil radius of Figure 4A is 1.5338 mm (ie, in Figure 2A, Figure 3A, and Figure 4A, the vertical axis is the most The large scale (the topmost scale) is 1.0135 mm, 1.4449 mm and 1.5338 mm). 2B, FIG. 3B and FIG. 4B are optical simulation data of field curvature and distortion with a wavelength of 588 nm, wherein the maximum angle of view (half angle) of FIG. 2B is 71.588 degrees. The maximum angle of view (half angle) of Figure 3B is 37.952 degrees, while the maximum field of view (half angle) of Figure 4B is 25.835 degrees. Further, in the graph of the field curvature, S represents data in the sagittal direction, and T represents data in the tangential direction. 2C, 3C, and 4C are optical simulation data plots of lateral chromatic aberrations simulated at wavelengths of 486, 588, and 656 nm, wherein the maximum image height of FIGS. 2C, 3C, and 4C (ie, the largest image on the reduction side) High) are both 3.41 mm. The patterns shown in FIGS. 2A to 4C are all within the standard range, whereby it can be verified that the zoom lens 100 of the present embodiment can indeed have good optical imaging quality.

5A to 5C are schematic diagrams showing the structure of a zoom lens at a wide angle end, an intermediate position, and a telephoto end, respectively, according to another embodiment of the present invention. Referring to FIGS. 5A to 5C, the zoom lens 100a of the present embodiment is similar to the zoom lens 100 of FIGS. 1A to 1C, and the main differences between the two are as follows. Referring to FIGS. 5A to 5C, in the second lens group 120a of the zoom lens 100a of the present embodiment, the eighth lens 124a is a biconcave lens, and the ninth lens 125a is a meniscus lens having a convex surface facing the magnification side. The zoom lens 100a of the present embodiment can also achieve the advantages and effects of the above-described zoom lens 100, and will not be repeated here.

An embodiment of the zoom lens 100a will be described below. It should be noted that the data listed in Tables 4, 5 and 6 below are not intended to limit this The invention, any one of ordinary skill in the art, may make appropriate changes to its parameters or settings after referring to the present invention, but it should still fall within the scope of the present invention.

The physical meanings of the parameters in Table 4 can be referred to the description of Table 1, and will not be repeated here. In addition, Table 5 lists the effective focal length, aperture value (F/#), field of view angle, and variable pitches d1, d2, and d3 of the zoom lens 100a at the wide-angle end, the intermediate position, and the telephoto end.

The above-mentioned surfaces S10, S11, S17 and S18 are even-order aspheric surfaces, and the formula is the same as the formula applicable to the above Table 3. In the present embodiment, the coefficient A ₂ is zero. Listed below in Table 6 are the aspherical parameter values of the surfaces S10, S11, S17, and S18 of the zoom lens 100a.

6A to 6C are optical simulation data diagrams of the zoom lens of FIG. 5A at the wide-angle end, and FIGS. 7A to 7C are optical simulation data diagrams of the zoom lens of FIG. 5B in the intermediate position, and FIGS. 8A to 8C are diagrams. Optical analog data of the 5C zoom lens at the telephoto end. Please refer to FIG. 6A to FIG. 8C , wherein FIG. 6A , FIG. 7A and FIG. 8A are simulation data diagrams of longitudinal aberrations simulated by a wavelength of 588 nm, wherein the aperture radius of FIG. 6A is 1.0033 mm, and the aperture of FIG. 7A is used. The radius is 1.4024 mm, and the aperture radius of Figure 8A is 1.4714 mm (i.e., in Figures 6A, 7A, and 8A, the maximum scale of the vertical axis (the topmost scale) is 1.0033 mm, 1.4024 mm, and 1.4714 mm, respectively. ). 6B, FIG. 7B and FIG. 8B are optical simulation data of field curvature and distortion with a wavelength of 588 nm, wherein the maximum angle of view (half angle) of FIG. 6B is 71.761 degrees, and the maximum angle of view of FIG. 7B. The (half angle) is 38.324 degrees, and the maximum angle of view (half angle) of Fig. 8B is 25.908 degrees. Further, in the graph of the field curvature, S represents data in the sagittal direction, and T represents data in the meridional direction. 6C, 7C, and 8C are optical simulation data plots of lateral chromatic aberrations simulated at wavelengths of 486, 588, and 656 nm, wherein the maximum image heights of FIGS. 6C, 7C, and 8C (ie, the largest image on the reduction side) High) are both 3.41 mm. The patterns shown in Figs. 6A to 8C are all within the standard range, whereby it can be verified that the zoom lens 100a of the present embodiment can surely have good optical imaging quality.

In summary, the zoom lens according to the embodiment of the present invention has a combination of diopter from the magnification side to the reduction side, which is negative, negative, negative, positive, positive, negative, positive, negative, and positive, and conforms to -2.8. <f1/fw<-2.3 and 0.6<| f1/f2 |<0.9, therefore, the zoom lens of the embodiment of the present invention has both a wide viewing angle and good image quality.

The above is only the preferred embodiment of the present invention, and the scope of the invention is not limited thereto, that is, the simple equivalent changes and modifications made by the scope of the invention and the description of the invention are All remain within the scope of the invention patent. In addition, any of the objects or advantages or features of the present invention are not required to be achieved by any embodiment or application of the invention. In addition, the abstract sections and headings are only used to assist in the search of patent documents and are not intended to limit the scope of the invention.

50‧‧‧ glass cover

60‧‧‧Image sensor

70‧‧‧Infrared light cut-off filter

80‧‧‧Transparent substrate

100‧‧‧ zoom lens

110‧‧‧First lens group

111‧‧‧First lens

112‧‧‧second lens

113‧‧‧ third lens

114‧‧‧Fourth lens

115, 126‧‧ ‧ double cemented lens

120‧‧‧second lens group

121‧‧‧ fifth lens

122‧‧‧ sixth lens

123‧‧‧ seventh lens

124‧‧‧ eighth lens

125‧‧‧ ninth lens

130‧‧‧ aperture diaphragm

A‧‧‧ optical axis

S1~S18‧‧‧ surface

Claims (11)

A zoom lens is disposed between an enlarged side and a reduced side, the zoom lens includes: a first lens group disposed between the enlarged side and the reduced side, and having a negative refracting power, the first lens The group includes a first lens, a second lens, a third lens and a fourth lens arranged in sequence from the magnification side to the reduction side, and the first lens, the second lens, the third lens and The diopter of the fourth lens is negative, negative, negative, and positive in sequence; and a second lens group disposed between the first lens group and the reduced side and having positive diopter, the second lens group including The magnification side sequentially arranges one of the fifth lens, the sixth lens, the seventh lens, the eighth lens, and the ninth lens to the reduced side, and the fifth lens, the sixth lens, and the seventh The diopter of the lens, the eighth lens and the ninth lens are positive, negative, positive, negative and positive, wherein the zoom lens conforms to -2.8<f1/fw<-2.3 and 0.6<| f1/f2 | 0.9, where f1 is the effective focal length of the first lens group, and f2 is the effective focal length of the second lens group And fw for the effective focal length of the zoom lens at the wide-angle end. The zoom lens of claim 1, wherein the first lens, the second lens, the third lens, and the fourth lens are spherical lenses, and the fifth lens, the sixth lens, the At least two of the seventh lens, the eighth lens, and the ninth lens are aspherical lenses. The zoom lens of claim 1, wherein the fifth lens is an aspherical lens. The zoom lens of claim 1, wherein the ninth lens is an aspherical lens. The zoom lens according to claim 1, further comprising an aperture stop disposed between the first lens group and the second lens group. The zoom lens of claim 5, wherein when the zoom lens is changed from the wide-angle end to the telephoto end, the position of the aperture stop remains unchanged with respect to the reduced side, and the first lens group and the The second lens group approaches the aperture stop. The zoom lens according to claim 1, wherein the second lens group is a zoom group, and the first lens group is a focus group. The zoom lens of claim 1, wherein the third lens and the fourth lens form a double cemented lens. The zoom lens of claim 1, wherein the sixth lens and the seventh lens form a double cemented lens. The zoom lens according to claim 1, wherein the first lens is a convex-concave lens having a convex surface facing the magnification side, the second lens is a biconcave lens, and the third lens is a convex-concave lens having a convex surface facing the magnification side, The fourth lens is a meniscus lens having a convex surface facing the magnification side, the fifth lens is a lenticular lens, the sixth lens is a convex-concave lens having a convex surface facing the magnification side, the seventh lens is a lenticular lens, and the eighth lens is a convex surface A convex-concave lens facing the magnification side, and the ninth lens is a lenticular lens. The zoom lens according to claim 1, wherein the first lens is a convex-concave lens having a convex surface facing the magnification side, the second lens is a biconcave lens, and the third lens is a convex-concave lens having a convex surface facing the magnification side, The fourth lens is convexly oriented The lenticular lens on the magnification side, the fifth lens is a lenticular lens, the sixth lens is a convex-concave lens having a convex surface facing the magnification side, the seventh lens is a lenticular lens, the eighth lens is a biconcave lens, and the ninth lens It is a meniscus lens whose convex surface faces the magnification side.