TWI537595B - Zoom lens - Google Patents

Description

Zoom lens

The invention relates to an optical lens; in particular to a zoom lens.

In recent years, the rapid advancement of semiconductor technology has made the images imaged by optical devices such as monitors more and more detailed, and the resolution and pixel requirements of the lenses of the above optical devices have been improved. More specifically, When the lens is short-focus, it is required to have a wide viewing angle, and it also needs to meet the low manufacturing cost and the demand for light, thin and short.

In addition, during the daytime, the optical device uses visible light as the light source for image capture, and at night, it uses near-infrared light as the light source for image capture, but due to some installation sites. The ambient light is too dim. In order to make the image after imaging have sufficient brightness, the lens of the above optical equipment usually needs to meet the design of large aperture, and at the same time cooperate with the frame design of the two mirror groups before and after the aperture, to achieve zoom. And the aforementioned optical requirements (e.g., U.S. Patent No. 8,395,847, U.S. Patent No. 8,184,379, U.S. Pat.

However, the design of the above patents is applied to an optical photosensitive element of 1/3 inch to 1/2.7 inch in an image format. However, when the number of pixels used in optical photosensitive elements exceeds 5 million, the size of the optical photosensitive element will become larger due to the small pixel size, and the size of the optical photosensitive element will increase. After the big, usually for the sake of good design and manufacture, the lens volume will be enlarged, and the production cost will also become higher. The needs of the field run counter to each other.

Therefore, from the above description, it can be known that when the application of the market goes to the high-order application of high-definition, the design of the conventional zoom lens is still not perfect, and it cannot effectively meet the market demand, and there is still room for improvement.

In view of the above, the object of the present invention is to provide a zoom lens having a large aperture characteristic from a wide-angle end to a telephoto end, and is applicable to a large-sized optical photosensitive element such as 1/2 inch, and the lens volume thereof. It can still be kept light and thin, and the total length is similar to that of the conventional lens design, and at the same time, it can correct the aberration of visible light to infrared light, and can maintain high resolution and large aperture, and has the advantages of easy manufacture and assembly.

In order to achieve the above object, the zoom lens of the present invention includes a first mirror group, an aperture, and a second mirror group arranged from an object side to an image side and sequentially along an optical axis. Wherein the first lens group has a negative refractive power, and the first lens, the second lens and the third lens are sequentially arranged from the object side to the image side; the first lens has a negative refractive power; The second lens has a negative refractive power; the third lens has a positive refractive power, and is adhered to the second lens to form a cemented lens having a negative refractive power; further, the first lens, the second lens and the third lens are The object side and the aperture move synchronously along the optical axis. The second mirror group has a positive refractive power, and a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, and a ninth are sequentially arranged from the object side to the image side. The fourth lens has a positive refractive power; the fifth lens has a negative refractive power; the sixth lens has a positive refractive power, and is adhered to the fifth lens to form a cemented lens having a negative refractive power; the seventh lens has Positive refractive power; the eighth lens has a negative refractive power; the ninth lens has a positive refractive power; further, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, and the ninth lens The sheet can be moved synchronously along the optical axis between the aperture and the image side.

In this way, through the lens design described above, the lens volume can be kept light and thin, and the total length is similar to that of the conventional lens design, and can be applied to a large-sized optical photosensitive element such as 1/2 inch, and at the same time By correcting the aberration of visible light to infrared light, it can maintain high resolution and large aperture, and at the same time has the advantages of easy manufacture and assembly.

1~5‧‧‧ zoom lens

G1‧‧‧ first mirror group

L1‧‧‧ first lens

L2‧‧‧ second lens

L3‧‧‧ third lens

L23‧‧‧ cemented lens

ST‧‧‧ aperture

G2‧‧‧Second mirror group

L4‧‧‧ fourth lens

L5‧‧‧ fifth lens

L6‧‧‧ sixth lens

L56‧‧‧ cemented lens

L7‧‧‧ seventh lens

L8‧‧‧ eighth lens

L9‧‧‧ ninth lens

Z‧‧‧ optical axis

1A is a lens structure diagram of a zoom lens of a first embodiment at a wide angle end; FIG. 1B is a lens structure diagram of a zoom lens of the first embodiment at a telephoto end; FIG. 2A is a distortion diagram of the first embodiment at a wide angle end; FIG. FIG. 2C is a longitudinal spherical aberration diagram of the first embodiment at the wide-angle end; FIG. 2D is a distortion diagram of the first embodiment at the telephoto end; FIG. 2E is a first implementation; FIG. 2F is a longitudinal spherical aberration diagram of the first embodiment at the telephoto end; FIG. 3A is a lens architecture diagram of the zoom lens of the second embodiment at the wide-angle end; FIG. 3B is a second embodiment; FIG. 4A is a distortion diagram of the second embodiment at the wide-angle end; FIG. 4B is a field curvature diagram of the second embodiment at the wide-angle end; FIG. 4C is a second embodiment of the second embodiment at the wide-angle end FIG. 4D is a distortion diagram of the second embodiment at the telephoto end; FIG. 4E is a field curvature diagram of the second embodiment at the distal end; FIG. 4F is a longitudinal view of the second embodiment at the distal end of the telephoto FIG. 5A is a lens structure diagram of a zoom lens of the third embodiment at a wide angle end; FIG. 5B is a zoom lens of the third embodiment; Telephoto lens architecture diagram; FIG. 6A is a third embodiment at the wide end of the distortion map; 6B is a field curvature diagram of the third embodiment at the wide-angle end; FIG. 6C is a longitudinal spherical aberration diagram of the third embodiment at the wide-angle end; FIG. 6D is a distortion diagram of the third embodiment at the telephoto end; FIG. FIG. 6F is a longitudinal spherical aberration diagram of the third embodiment at the distal end; FIG. 7A is a lens architecture diagram of the zoom lens of the fourth embodiment at the wide-angle end; FIG. 7B is a fourth embodiment; FIG. 8A is a distortion diagram of the fourth embodiment at the wide-angle end; FIG. 8B is a field curvature diagram of the fourth embodiment at the wide-angle end; FIG. 8C is a fourth embodiment of the fourth embodiment a longitudinal spherical aberration diagram at the wide-angle end; FIG. 8D is a distortion diagram of the fourth embodiment at the telephoto end; FIG. 8E is a field curvature diagram of the fourth embodiment at the distal end; FIG. 8F is a fourth embodiment of the telephoto end FIG. 9A is a lens structure diagram of a zoom lens of the fifth embodiment at a wide angle end; FIG. 9B is a lens structure diagram of a zoom lens of the fifth embodiment at a telephoto end; FIG. 10A is a fifth embodiment of the lens at a wide angle end FIG. 10B is a field curvature diagram of the fifth embodiment at the wide angle end; FIG. 10C is a longitudinal spherical aberration of the fifth embodiment at the wide angle end ; FIG. 10D is a fifth embodiment of the distortion in the telephoto end; Figure 10E is a field curvature of the embodiment of FIG telephoto end to the fifth embodiment; FIG. 10F is a fifth embodiment of the camera in the distal end of the longitudinal spherical aberration diagram.

It should be noted that the distortion map, the field curvature map and the longitudinal spherical aberration diagram of the above are all the optical simulation data obtained when the light wavelength is 587 nm.

In order to explain the present invention more clearly, the following embodiments will be described in detail with reference to the accompanying drawings. Referring to FIGS. 1A and FIG. 1B, FIG. 3A and FIG. 3B, FIG. 5A and FIG. 5B, FIG. 7A and FIG. Figure 9A and Figure 9 B shows the lens structures of the zoom lenses 1 to 5 of the first to fifth embodiments of the present invention at the wide-angle end and the telephoto end, respectively, wherein the zoom lenses 1 to 5 respectively include an object side to One image side G1, one aperture ST, and one second mirror group G2 are sequentially arranged on one image side and along an optical axis Z. In addition, depending on the requirements of use, an optical filter (such as an aperture position, an interval between the second mirror group G2 and the image side) may be disposed in the zoom lenses 1 to 5 to filter Eliminate unnecessary noise light, and achieve the purpose of improving optical performance. Of course, the position of the filter can be changed according to different design requirements, and is not limited to the above. Wherein: the first mirror group G1 has a negative refractive power, and one of the first lens L1, the second lens L2 and the third lens L3 is sequentially arranged from the object side to the image side, and the first mirror The first lens L1, the second lens L2 and the third lens L3 of the group G1 are synchronously movable along the optical axis Z between the object side and the aperture ST.

More specifically, the first lens L1 is a convex-concave lens having a negative refractive power, and its convex surface S1 faces the object side, and the concave surface S2 faces the image side.

The second lens L2 is a biconcave lens having a negative refractive power.

The third lens L3 is a convex-concave lens having a positive refractive power, and the convex surface S4 is directed toward the object side and adheres to the concave surface S4 of the second lens L2 toward the image side to form a cemented lens L23 having a negative refractive power, and is worth It is noted that, by the above-mentioned design that the second lens L2 of the negative refractive power and the third lens L3 of the positive refractive power are adhered and arranged behind the first lens L1, the first mirror group G1 can be effectively eliminated. The effect of Axial chromatic aberration.

The second mirror group G2 has a positive refractive power, and a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, and an eighth are sequentially arranged from the object side to the image side. Lens L8 and a ninth lens The fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7, the eighth lens L8, and the ninth lens L9 of the second mirror group G2 are The aperture ST and the image side are synchronously moved along the optical axis Z, thereby adjusting the imaging magnification of each of the zoom lenses 1 to 5, so that each of the zoom lenses 1 to 5 exhibits a wide angle end to a telephoto end ( Telephoto) magnification changes.

In addition, when the zoom lenses 1 to 5 adjust the magnification and drive the second lens group G2 to move along the optical axis Z between the image side and the aperture ST, the zoom lenses 1 to 5 are optically When the magnification changes and the imaging plane shifts, the effect of the imaging plane correction can be achieved by moving the first mirror group G1.

More specifically, the fourth lens L4 is a lenticular lens having positive refractive power, and the two mirror surfaces S7, S8 are all aspherical surfaces.

The fifth lens L5 is a convex-concave lens having a negative refractive power, and its convex surface S9 faces the object side, and the concave surface S10 faces the image side.

The sixth lens L6 is a lenticular lens having a positive refractive power, and the convex surface S10 facing the object side and the concave surface S10 of the fifth lens L5 facing the image side are bonded to form a cemented lens L56 having a negative refractive power, and here The purpose of designing the cemented lens L56 is to effectively suppress the axial chromatic aberration generated by the second mirror group G2 through the optical effect of the lens structure of the cemented lens L56.

The seventh lens L7 is a convex-concave lens having a positive refractive power, and a convex surface S13 faces the image side, and a concave surface S12 faces the object side. It is worth mentioning that the seventh lens L7, which also has a positive refractive power, is arranged after the sixth lens L6 of the positive refractive power, so as to effectively share the diopter of the sixth lens L6 in the optical system. In addition to enhancing the suppression of aberrations, the sixth lens L6 can be prevented from being excessively bent due to excessive refractive power, thereby effectively reducing the manufacturing difficulty of the sixth lens L6 and improving the zoom lens. 1~5 error tolerance during assembly Allowed value.

The eighth lens L8 is a convex-concave lens having a negative refractive power, and its convex surface S14 faces the object side, and the concave surface S15 faces the image side.

The ninth lens L9 is a convex-concave lens having a positive refractive power, and the convex surface S16 faces the object side, and the concave surface S17 faces the image side, and the two mirror surfaces S16 and S17 are all aspherical surfaces.

In order to effectively improve the optical performance of the zoom lenses 1 to 5, the zoom lenses R of the respective lens surfaces of the zoom lenses 1 to 5 of the first to fifth embodiments of the present invention have a radius of curvature R, a mirror surface, and a mirror surface (or The imaging surface) is the distance D on the optical axis Z, the refractive index Nd of each lens, the Abbe's coefficient Vd of each lens, and the effective focal length F and the aperture coefficient of each of the zoom lenses 1 to 5 at the wide-angle end and the telephoto end. And the viewable FOV (2 ω), as shown in Tables 1 to 5:

In addition, in each of the lenses of the zoom lenses 1 to 5 of the respective embodiments, the surface depression z of the aspherical surfaces S7, S8, S16, and S17 is obtained by the following formula:

Where: z: the degree of depression of the aspherical surface; c: the reciprocal of the radius of curvature; h: the off-axis half-height of the surface; k: the conic coefficient; A~J: the coefficient of each step of the off-axis half-height of the surface.

The aspherical coefficients k and the respective order coefficients A to J of the respective aspherical surfaces S7, S8, S16 and S17 of the zoom lenses 1 to 5 of the first to fifth embodiments of the present invention are as shown in Tables 6 to 10:

Table ten

In addition, in addition to the above optical specifications, the zoom lenses 1~5 are designed to meet the following conditional specifications, so that the image can achieve better image quality, thereby effectively reducing the lens volume and wide-angle effect: (1)- 1.2<F/f1<-0.4; (2)Vd6>63; (3)Vd6-Vd5>40; (4)Vd9>63; where F is the focal length of the zoom lens 1~5; f1 is the first The focal length of the mirror group G1; Vd5 is the Abbe's coefficient of the fifth lens L5; Vd6 is the Abbe's coefficient of the sixth lens L6; and Vd9 is the Abbe's coefficient of the ninth lens L9.

The design condition of the above conditional expression is that if the zoom lenses 1 to 5 satisfy the formula (1), the volume of the system can be effectively reduced, and the aberration can be effectively suppressed. In more detail, if the zoom lenses 1 to 5 exceed the upper limit of the formula (1), the refractive power of the first mirror group G1 will become too weak, so that the stroke required for the zooming process becomes long, which is disadvantageous for reduction. System volume. On the other hand, if it is lower than the lower limit of the formula (1), the refractive power of the first mirror group G1 will become too strong, and the aberration cannot be effectively suppressed.

In addition, if the zoom lenses 1 to 5 cannot satisfy the equations (2) and (3), the effect of suppressing the axial chromatic aberration is inconspicuous, and the visible light to the infrared wave The aberration of the segment will also be magnified, resulting in poor lens imaging quality.

Further, if the Abbe's coefficient of the ninth lens L9 is lower than the range of the formula (4), the chromatic aberration will be poorly expressed. Therefore, through the design of the formula (4) and the shape of the ninth lens L9, various aberrations of the optical system close to the imaging surface can be effectively eliminated, and the optical performance of the zoom lenses 1 to 5 can be satisfied. Optical requirements for megapixel optical sensing elements.

Further, the detailed data of the above-described conditions of the zoom lenses 1 to 5 of the first to fifth embodiments of the present invention are as shown in Table 11:

In this way, referring to FIG. 2A to FIG. 2C, it can be seen that the zoom lens 1 of the first embodiment can meet the requirements of the imaging quality at the wide-angle end by the above design, wherein, as can be seen from FIG. 2A, The maximum distortion of the zoom lens 1 does not exceed -100% and 0%. As can be seen from FIG. 2B, the maximum field curvature of the zoom lens 1 does not exceed -0.10 mm and 0.10 mm. As can be seen from FIG. 2C, the maximum longitudinal spherical aberration of the zoom lens 1 does not exceed -0.20 mm and 0.10 mm.

In addition, referring to FIG. 2D to FIG. 2F, it can be seen that the zoom lens 1 of the first embodiment can achieve the imaging quality at the distal end by the above design, wherein the zoom can be seen from FIG. 2D. The maximum distortion of lens 1 does not exceed -50% and 0%. As can be seen from FIG. 2E, the maximum field curvature of the zoom lens 1 does not exceed -0.10 mm and 0.10 mm. As can be seen from FIG. 2F, the longitudinal spherical aberration of the zoom lens 1 does not exceed -0.10 mm and 0.10 mm.

4A to FIG. 4C, it can be seen that the zoom lens 2 of the second embodiment can achieve the imaging quality at the wide-angle end by the above design. As can be seen from FIG. 4A, the zoom lens 2 can be seen. The maximum distortion variable does not exceed -100% and 0%. As can be seen from FIG. 4B, the maximum field curvature of the zoom lens 2 does not exceed -0.10 mm and 0.10 mm; as can be seen from FIG. 4C, the maximum longitudinal spherical aberration of the zoom lens 2 does not exceed -0.10 mm and 0.10 mm.

In addition, referring to FIG. 4D to FIG. 4F, it can be seen that the zoom lens 2 of the second embodiment can achieve the imaging quality at the distal end by the above design, wherein the zoom can be seen from FIG. 4D. The maximum distortion of lens 2 does not exceed -50% and 0%. As can be seen from FIG. 4E, the maximum field curvature of the zoom lens 2 does not exceed -0.20 mm and 0.10 mm. As can be seen from FIG. 4F, the longitudinal spherical aberration of the zoom lens 2 does not exceed 0 mm and 0.10 mm.

6A to FIG. 6C, it can be seen that the zoom lens 3 of the third embodiment can achieve the imaging quality at the wide-angle end by the above design. As can be seen from FIG. 6A, the zoom lens 3 can be seen. The maximum distortion variable does not exceed -100% and 0%. As can be seen from FIG. 6B, the maximum field curvature of the zoom lens 3 does not exceed -0.10 mm and 0.10 mm. As can be seen from FIG. 6C, the maximum longitudinal spherical aberration of the zoom lens 3 does not exceed -0.10 mm and 0.10 mm.

In addition, referring to FIG. 6D to FIG. 6F, it can be seen that the zoom lens 3 of the third embodiment can achieve the imaging quality at the distal end by the above design, wherein the zoom can be seen from FIG. 6D. The maximum distortion of lens 3 does not exceed -50% and 0%. As can be seen from FIG. 6E, the maximum field curvature of the zoom lens 3 does not exceed -0.10 mm and 0.10 mm. As can be seen from FIG. 6F, the longitudinal spherical aberration of the zoom lens 3 does not exceed 0 mm and 0.10 mm.

8A to FIG. 8C, it can be seen that the zoom lens 4 of the fourth embodiment can achieve the imaging quality at the wide-angle end by the above design. As can be seen from FIG. 8A, the zoom lens 4 can be seen. The maximum distortion variable does not exceed -100% and 0%. As can be seen from FIG. 8B, the zoom lens 4 The maximum field curvature is no more than -0.20mm and 0.20mm. As can be seen from FIG. 8C, the maximum longitudinal spherical aberration of the zoom lens 4 does not exceed 0 mm and 0.10 mm.

In addition, referring to FIG. 8D to FIG. 8F, it can be seen that the zoom lens 4 of the fourth embodiment can achieve the imaging quality at the distal end by the above design, wherein the zoom can be seen from FIG. 8D. The maximum distortion of lens 4 does not exceed -50% and 0%. As can be seen from FIG. 8E, the maximum field curvature of the zoom lens 4 does not exceed -0.20 mm and 0.10 mm. As can be seen from FIG. 8F, the longitudinal spherical aberration of the zoom lens 4 does not exceed 0 mm and 0.10 mm.

10A to FIG. 10C, it can be seen that the zoom lens 5 of the fifth embodiment can achieve the imaging quality at the wide-angle end by the above design. As can be seen from FIG. 10A, the zoom lens 5 can be seen. The maximum distortion variable does not exceed -100% and 0%. As can be seen from FIG. 10B, the maximum field curvature of the zoom lens 5 does not exceed -0.10 mm and 0.20 mm. As can be seen from FIG. 10C, the maximum longitudinal spherical aberration of the zoom lens 5 does not exceed -0.10 mm and 0.10 mm.

In addition, referring to FIG. 10D to FIG. 10F, it can be seen that the zoom lens 5 of the fifth embodiment can achieve the imaging quality at the distal end by the above design, wherein the zoom can be seen from FIG. 10D. The maximum distortion of lens 5 does not exceed -50% and 0%. As can be seen from FIG. 10E, the maximum field curvature of the zoom lens 5 does not exceed -0.10 mm and 0.10 mm. As can be seen from FIG. 10F, the longitudinal spherical aberration of the zoom lens 5 does not exceed 0 mm and 0.10 mm.

In summary, the zoom lens 1~5 of the present invention can have a large aperture effect from the wide-angle end to the telephoto end through the above-mentioned lens structure, lens material and optical condition design, and can be applied to Such as 1/2 inch large-size optical sensor, and its lens volume can still be kept light and thin, and at the same time can correct the aberration of visible light to infrared light, more maintain high resolution and large aperture, and at the same time easy The advantages of manufacturing and assembly.

It should be noted that the above description is only a preferred embodiment of the present invention, and is not limited to the contents of the above embodiments, and the application is applicable. Equivalent variations of the present specification and claims are intended to be included within the scope of the invention.

1‧‧‧ zoom lens

G1‧‧‧ first mirror group

L1‧‧‧ first lens

L2‧‧‧ second lens

L3‧‧‧ third lens

L23‧‧‧ cemented lens

ST‧‧‧ aperture

G2‧‧‧Second mirror group

L4‧‧‧ fourth lens

L5‧‧‧ fifth lens

L6‧‧‧ sixth lens

L56‧‧‧ cemented lens

L7‧‧‧ seventh lens

L8‧‧‧ eighth lens

L9‧‧‧ ninth lens

Z‧‧‧ optical axis

Claims (10)

A zoom lens includes a first mirror group, an aperture, and a second mirror group arranged from an object side to an image side and along an optical axis, wherein: the first mirror group has a negative refractive power, and Forming, by the object side to the image side, one of the first lens, the second lens and the third lens; the first lens has a negative refractive power; the second lens has a negative refractive power; the third lens has Positive refractive power, and is glued to the second lens to form a cemented lens having a negative refractive power; further, the first lens, the second lens and the third lens may be along the optical axis between the object side and the aperture Synchronous movement; and the second mirror group has a positive refractive power, and a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens are sequentially arranged from the object side to the image side And a ninth lens; the fourth lens has a positive refractive power; the fifth lens has a negative refractive power; the sixth lens has a positive refractive power, and is adhered to the fifth lens to form a cemented lens having a negative refractive power; The seventh lens has positive flexion The eighth lens has a negative refractive power; the ninth lens has a positive refractive power; further, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, and the ninth lens are The optical axis and the image side move synchronously along the optical axis. The zoom lens of claim 1, wherein the first lens is a convex-concave lens and has a convex surface facing the object side; the second lens is a double concave lens; the third lens is a convex-concave lens, and the convex surface is convex The object side is bonded to the concave surface of the second lens toward the image side. The zoom lens of claim 1, wherein the fourth lens is a lenticular lens; the fifth lens is a convex-concave lens with a convex surface facing the object side; the sixth lens is a lenticular lens, and facing the object The convex surface of the side is bonded to the concave surface of the fifth lens toward the image side; the seventh lens is a convex-concave lens with a convex surface facing the image side; the eighth lens is a convex-concave lens with a convex surface facing the object side; The ninth lens is a convex-concave lens with a convex surface facing the object side. The zoom lens of claim 3, wherein the fourth lens has at least one mirror surface that is an aspherical surface. The zoom lens of claim 4, wherein the second mirror surface of the fourth lens is an aspherical surface. The zoom lens of claim 3, wherein the ninth lens has at least one mirror surface that is an aspherical surface. The zoom lens of claim 6, wherein the second mirror surface of the ninth lens is an aspherical surface. The zoom lens of claim 1, wherein the fifth lens and the sixth lens satisfy the following conditions: Vd6>63; and Vd6-Vd5>40; wherein Vd5 is an Abbe coefficient of the fifth lens; Vd6 Is the Abbe coefficient of the sixth lens. The zoom lens of claim 1, wherein the ninth lens further satisfies the following condition: Vd9>63; wherein Vd9 is an Abbe coefficient of the ninth lens. The zoom lens according to claim 1 further satisfies the following condition: -1.2 < F / f1 < - 0.4; wherein F is the focal length of the zoom lens; f1 is the focal length of the first mirror group.