CN111175953B - Ultra-small zoom lens - Google Patents

Abstract

The invention discloses an ultra-small zoom lens, which adopts a glass-plastic mixed 9-piece design, and sequentially comprises a first lens, a second lens, a third lens, a fourth lens, a diaphragm, a fifth lens, a sixth lens, a seventh lens, an eighth lens and a ninth lens from an object side to an image side, wherein the first lens, the second lens, the third lens, the seventh lens and the ninth lens have negative refractive indexes, and the fourth lens, the fifth lens, the sixth lens and the eighth lens have positive refractive indexes. The design can effectively shorten the length of the lens and maintain the performance of the system, and covers common short-focus use focus segments, such as 2.8mm, 3.6mm, 4mm, 6mm, 8mm and the like, so that the overall application range of the lens is wider and the cost performance is extremely high.

Description

An ultra-small zoom lens

Technical Field

The invention belongs to the technical field of security monitoring, and in particular relates to an ultra-small zoom lens.

Background Art

Surveillance cameras are being used more and more frequently, and demands have gradually been raised for 24-hour continuous monitoring, monitoring in low-light environments, and monitoring with a wide field of view, which in turn has escalated to the trend of requiring high-definition surveillance images.

In factories, buildings, and parking lots that require 24-hour continuous monitoring, there is an increasing demand for small, high-definition day and night cameras. The advantage of day and night cameras is that even in low-light environments or even in environments without visible light, clear images can be observed by using night mode (black and white images at night) and using near-infrared lights to illuminate the monitored object. At the same time, it is possible to not only observe the monitored object, but also to identify the monitored object.

If a normal daily-use lens is mounted on a day-and-night camera, the focus will be off-focus when the night mode is used due to the influence of longitudinal chromatic aberration, and a clear image cannot be captured. In order to avoid off-focus and enable the lens to be used in day-and-night cameras, it is necessary to minimize longitudinal chromatic aberration from the visible light region to the near-infrared light region.

The obvious defects of the optical surveillance lenses currently on the market are that the total length (TTL) of the optical lens is too large and there are too many lenses, which makes the overall cost of the lens too high and the size too large, affecting its use; the transfer function is not well controlled, the resolution is low, the image sharpness is poor, and the image is uneven; the focal length span is small, the field of view angle span is small, and the switching flexibility is poor; the infrared confocality is poor, the defocus amount is large when switching to visible infrared, and the image quality is poor when using infrared; and the variable magnification is low, the focal length coverage is incomplete, and the practicality is not high.

Therefore, the present invention provides a new ultra-small zoom monitoring lens for day and night use.

Summary of the invention

In order to improve the existing surveillance lens, the present invention provides an ultra-small zoom lens, which includes, from the object side to the image side, a first lens, a second lens, a third lens, a fourth lens, an aperture, a fifth lens, a sixth lens, a seventh lens, an eighth lens and a ninth lens;

The first lens has a negative refractive power, and has an object-side surface facing the object side and an image-side surface facing the image side, wherein the object-side surface is a convex surface and the image-side surface is a concave surface;

The second lens has a negative refractive power, and has an object-side surface facing the object side and an image-side surface facing the image side, wherein the object-side surface is a concave surface and the image-side surface is a concave surface;

The third lens has a negative refractive power, and has an object-side surface facing the object side and an image-side surface facing the image side, wherein the object-side surface is a convex surface and the image-side surface is a concave surface;

The fourth lens has a positive refractive power, and has an object-side surface facing the object side and an image-side surface facing the image side, wherein the object-side surface is a convex surface and the image-side surface is a convex surface;

The fifth lens has a positive refractive power, and has an object-side surface facing the object side and an image-side surface facing the image side, wherein the object-side surface is a convex surface and the image-side surface is a concave surface;

The sixth lens has a positive refractive power, and has an object-side surface facing the object side and an image-side surface facing the image side, wherein the object-side surface is a convex surface and the image-side surface is a convex surface;

The seventh lens element has a negative refractive power, and has an object-side surface facing the object side and an image-side surface facing the image side, wherein the object-side surface is a concave surface and the image-side surface is a concave surface;

The eighth lens has a positive refractive power, and has an object-side surface facing the object side and an image-side surface facing the image side, wherein the object-side surface is a convex surface and the image-side surface is a convex surface;

The ninth lens element has a negative refractive power and comprises an object-side surface facing the object side and an image-side surface facing the image side. The object-side surface is a concave surface, and the image-side surface is a convex surface.

The first to fourth lenses constitute a focusing lens group; the fifth to ninth lenses constitute a variable magnification lens group.

This ultra-compact zoom lens has only the above-mentioned nine lenses.

Preferably, the ultra-small zoom lens further satisfies: the third lens and the fourth lens are glued to each other.

Preferably, the ultra-small zoom lens further satisfies: the sixth lens and the seventh lens are glued to each other.

Preferably, the ultra-small zoom lens also satisfies: |vd4-vd3|>30, wherein vd3 and vd4 are the dispersion coefficients of the third lens and the fourth lens respectively.

Preferably, the ultra-small zoom lens also satisfies: |vd7-vd6|>30, wherein vd6 and vd7 are the dispersion coefficients of the sixth lens and the seventh lens respectively.

Preferably, the ultra-small zoom lens further satisfies: the third lens and the ninth lens are 16-order even-order plastic aspherical designs.

Preferably, the ultra-small zoom lens further satisfies: the first lens and the seventh lens are both made of high refractive index materials, nd1=1.835, nd7=1.847, wherein nd1 is the refractive index of the first lens, and nd7 is the refractive index of the seventh lens.

Preferably, the ultra-small zoom lens also satisfies: the second lens, the third lens and the sixth lens all use materials with relatively large dispersion coefficients, wherein vd2=58.35, vd3=59.51, vd6=51.16, and vd2, vd3 and vd6 are the dispersion coefficients of the second lens, the third lens and the sixth lens respectively.

The beneficial effects of the present invention are:

1. The optical TTL is less than 33mm, and the glass-plastic hybrid 9-piece design makes the lens small in size and low in manufacturing cost;

2. Good control of transfer function, high resolution (2K), high resolution, high image sharpness and uniform image;

3. Wide focal length span, wide field of view span, and strong switching flexibility;

4. Use a switch sheet to switch between visible and infrared to improve the quality of infrared imaging.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

FIG1 is a schematic diagram of the structure of the first embodiment of the present invention at the shortest focal length;

FIG2 is a schematic diagram of the structure of the first embodiment of the present invention at the longest focal length;

FIG3 is an MTF diagram of visible light 0.450-0.650 μm at the shortest focal length according to the first embodiment of the present invention;

FIG4 is a defocus curve diagram of visible light 0.450-0.650 μm at the shortest focal length according to the first embodiment of the present invention;

FIG5 is an MTF diagram of infrared 850nm at the shortest focal length of the first embodiment of the present invention;

FIG6 is a defocus curve diagram of infrared light of 850 nm at the shortest focal length according to the first embodiment of the present invention;

FIG7 is a lateral chromatic aberration curve diagram of the first embodiment of the present invention at the shortest focal length;

FIG8 is a schematic diagram of a longitudinal aberration diagram of Embodiment 1 of the present invention at the shortest focal length;

FIG9 is an MTF diagram of visible light 0.450-0.650 μm at the longest focal length according to the first embodiment of the present invention;

FIG10 is a defocus curve diagram of visible light 0.450-0.650 μm at the longest focal length according to the first embodiment of the present invention;

FIG11 is an MTF diagram of infrared 850nm at the longest focal length of Example 1 of the present invention;

FIG12 is a defocus curve diagram of infrared light of 850 nm at the longest focal length according to the first embodiment of the present invention;

FIG13 is a lateral chromatic aberration curve diagram of the first embodiment of the present invention at the longest focal length;

FIG14 is a schematic diagram of a longitudinal aberration diagram of Embodiment 1 of the present invention at the longest focal length;

FIG15 is a schematic diagram of the structure of the second embodiment of the present invention when the focal length is the shortest;

FIG16 is a schematic diagram of the structure of the second embodiment of the present invention at the longest focal length;

FIG17 is an MTF diagram of visible light 0.450-0.650 μm at the shortest focal length according to the second embodiment of the present invention;

FIG18 is a defocus curve diagram of visible light 0.450-0.650 μm at the shortest focal length according to the second embodiment of the present invention;

FIG19 is an MTF diagram of infrared 850nm at the shortest focal length of Example 2 of the present invention;

FIG20 is a defocus curve diagram of infrared light of 850 nm at the shortest focal length according to the second embodiment of the present invention;

FIG21 is a lateral chromatic aberration curve diagram of Embodiment 2 of the present invention at the shortest focal length;

FIG22 is a schematic diagram of a longitudinal aberration diagram of Embodiment 2 of the present invention at the shortest focal length;

FIG23 is an MTF diagram of visible light 0.450-0.656 μm at the longest focal length according to the second embodiment of the present invention;

FIG24 is a defocus curve diagram of visible light 0.450-0.656 μm at the longest focal length according to the second embodiment of the present invention;

FIG25 is an MTF diagram of infrared 850nm at the longest focal length of Example 2 of the present invention;

FIG26 is a defocus curve diagram of infrared light of 850 nm at the longest focal length according to the second embodiment of the present invention;

FIG27 is a lateral chromatic aberration curve diagram of Embodiment 2 of the present invention at the longest focal length;

FIG28 is a schematic diagram of a longitudinal aberration diagram of Embodiment 2 of the present invention at the longest focal length;

FIG29 is a schematic diagram of the structure of Embodiment 3 of the present invention when the focal length is the shortest;

FIG30 is a schematic diagram of the structure of Embodiment 3 of the present invention when it is at the longest focal length;

FIG31 is an MTF diagram of visible light 0.450-0.650 μm at the shortest focal length according to Embodiment 3 of the present invention;

FIG32 is a defocus curve diagram of visible light 0.450-0.650 μm at the shortest focal length according to Embodiment 3 of the present invention;

FIG33 is an MTF diagram of infrared 850nm at the shortest focal length of Example 3 of the present invention;

FIG34 is a defocus curve diagram of infrared light of 850 nm at the shortest focal length according to Embodiment 3 of the present invention;

FIG35 is a lateral chromatic aberration curve diagram of Embodiment 3 of the present invention at the shortest focal length;

FIG36 is a schematic diagram of a longitudinal aberration diagram of Embodiment 3 of the present invention at the shortest focal length;

FIG37 is an MTF diagram of visible light 0.450-0.656 μm at the longest focal length according to Embodiment 3 of the present invention;

FIG38 is a defocus curve diagram of visible light 0.450-0.656 μm at the longest focal length according to Embodiment 3 of the present invention;

FIG39 is an MTF diagram of infrared 850nm at the longest focal length of Example 3 of the present invention;

FIG40 is a defocus curve diagram of infrared light of 850 nm at the longest focal length according to Embodiment 3 of the present invention;

FIG41 is a lateral chromatic aberration curve diagram of Embodiment 3 of the present invention at the longest focal length;

FIG42 is a schematic diagram of a longitudinal aberration diagram of Embodiment 3 of the present invention at the longest focal length;

FIG43 is a schematic diagram of the structure of Embodiment 4 of the present invention when the focal length is the shortest;

FIG44 is a schematic diagram of the structure of Embodiment 4 of the present invention when it is at the longest focal length;

FIG45 is an MTF diagram of visible light 0.450-0.650 μm at the shortest focal length according to Embodiment 4 of the present invention;

FIG46 is a defocus curve diagram of visible light 0.450-0.650 μm at the shortest focal length according to Embodiment 4 of the present invention;

FIG47 is an MTF diagram of infrared 850nm at the shortest focal length of Example 4 of the present invention;

FIG48 is a defocus curve diagram of infrared light of 850 nm at the shortest focal length according to the fourth embodiment of the present invention;

FIG49 is a lateral chromatic aberration curve diagram of Embodiment 4 of the present invention at the shortest focal length;

FIG50 is a schematic diagram of a longitudinal aberration diagram of Embodiment 4 of the present invention at the shortest focal length;

FIG51 is an MTF diagram of visible light 0.450-0.656 μm at the longest focal length according to the fourth embodiment of the present invention;

FIG52 is a defocus curve diagram of visible light 0.450-0.656 μm at the longest focal length according to Embodiment 4 of the present invention;

FIG53 is an MTF diagram of infrared 850nm at the longest focal length of Example 4 of the present invention;

FIG54 is a defocus curve diagram of infrared light of 850 nm at the longest focal length according to the fourth embodiment of the present invention;

FIG55 is a lateral chromatic aberration curve diagram of Embodiment 4 of the present invention at the longest focal length;

FIG56 is a schematic diagram of the longitudinal aberration diagram of Example 4 of the present invention at the longest focal length.

DETAILED DESCRIPTION

To further illustrate the various embodiments, the present invention provides drawings. These drawings are part of the disclosure of the present invention, which are mainly used to illustrate the embodiments and can be used in conjunction with the relevant descriptions in the specification to explain the operating principles of the embodiments. With reference to these contents, a person of ordinary skill in the art should be able to understand other possible implementations and advantages of the present invention. The components in the figures are not drawn to scale, and similar component symbols are generally used to represent similar components.

The present invention will now be further described with reference to the accompanying drawings and specific implementation methods.

The term "a lens having a positive refractive power (or a negative refractive power)" means that the paraxial refractive power of the lens calculated by Gaussian optical theory is positive (or negative). The term "object side (or image side) of the lens" is defined as a specific range of the lens surface through which the imaging light passes. The concave and convex shape of the lens can be determined by the judgment method of the general knowledgeable person in this field, that is, the concave and convex shape of the lens surface can be determined by the positive and negative signs of the radius of curvature (abbreviated as R value). R value can be commonly used in optical design software, such as Zemax or CodeV. R value is also commonly found in the lens data sheet of optical design software. For the object side, when the R value is positive, the object side is determined to be convex; when the R value is negative, the object side is determined to be concave. Conversely, for the image side, when the R value is positive, the image side is determined to be concave; when the R value is negative, the image side is determined to be convex.

The present invention provides an ultra-small zoom lens, which comprises, from the object side to the image side, a first lens, a second lens, a third lens, a fourth lens, an aperture, a fifth lens, a sixth lens, a seventh lens, an eighth lens and a ninth lens.

The first lens has negative refractive power, an object side surface facing the object side and an image side surface facing the image side, the object side surface has a convex portion in the vicinity of the circumference, and the image side surface has a concave portion in the vicinity of the optical axis.

The second lens has negative refractive power, an object side surface facing the object side and an image side surface facing the image side, the object side surface has a concave portion in the vicinity of the circumference, and the image side surface has a concave portion in the vicinity of the optical axis.

The third lens has negative refractive power, an object side surface facing the object side and an image side surface facing the image side, the object side surface has a convex portion in the vicinity of the circumference, and the image side surface has a concave portion in the vicinity of the optical axis.

The fourth lens has positive refractive power, and has an object side surface facing the object side and an image side surface facing the image side. The object side surface has a convex portion in a region near the circumference, and the image side surface has a concave portion in a region near the optical axis.

The fifth lens has positive refractive power, and has an object-side surface facing the object side and an image-side surface facing the image side. The object-side surface has a convex portion in a region near the circumference, and the image-side surface has a concave portion in a region near the optical axis.

The sixth lens has positive refractive power, and has an object-side surface facing the object side and an image-side surface facing the image side. The object-side surface has a convex portion in a region near the circumference, and the image-side surface has a convex portion in a region near the optical axis.

The seventh lens has negative refractive power, and has an object-side surface facing the object side and an image-side surface facing the image side. The object-side surface has a concave portion in a region near the circumference, and the image-side surface has a concave portion in a region near the optical axis.

The eighth lens has positive refractive power, and has an object-side surface facing the object side and an image-side surface facing the image side. The object-side surface has a convex portion in a region near the circumference, and the image-side surface has a convex portion in a region near the optical axis.

The ninth lens has negative refractive power, and has an object-side surface facing the object side and an image-side surface facing the image side. The object-side surface has a concave portion in a region near the circumference, and the image-side surface has a convex portion in a region near the optical axis.

The first to fourth lenses constitute a focusing lens group; the fifth to ninth lenses constitute a variable magnification lens group.

The present invention adopts nine lenses, and through the arrangement design of the refractive power and surface shape of each lens, has the advantages of optical TTL less than 33mm, small overall lens volume, and low manufacturing cost; good control of transfer function, high resolution (2K), high resolution, high image sharpness, and uniform image; large focal length span, large field of view angle span, and strong switching flexibility; using a switching piece to switch between visible and infrared to improve infrared imaging quality, etc., and the design adopts a two-component zoom design, the image quality is stable during the zoom process, and the structural design is simple, which is conducive to large-scale mass production.

Preferably, the ultra-small zoom lens also satisfies: the third and fourth lenses are cemented sheets, and |vd4-vd3|>30, wherein vd3 and vd4 are the dispersion coefficients of the third lens and the fourth lens respectively, which is conducive to correcting chromatic aberration.

Preferably, the ultra-small zoom lens also satisfies: the sixth and seventh lenses are cemented sheets, and |vd7-vd6|>30, wherein vd6 and vd7 are the dispersion coefficients of the sixth lens and the seventh lens respectively, which is conducive to correcting chromatic aberration.

Preferably, the ultra-small zoom lens also meets the following requirements: the third lens and the ninth lens are 16-order even-order plastic aspherical designs, which are useful for correcting secondary spectra and higher-order aberrations, and are also beneficial for lens structure design and reducing lens costs.

Preferably, the ultra-small zoom lens also satisfies: nd1=1.835, nd7=1.847, and the first lens and the seventh lens are both made of high refractive index materials, which can better optimize the optical structure.

Preferably, the ultra-small zoom lens also satisfies: vd2=58.35, vd3=59.51, vd6=51.16, and the second lens, the third lens and the sixth lens are all made of materials with a large dispersion coefficient, which is beneficial to reducing the dispersion of light and optimizing chromatic aberration.

Preferably, the lens in the design uses a visible-infrared switching plate design, taking into account both visible and infrared imaging quality and improving the overall imaging quality.

The zoom lens of the present invention will be described in detail below with reference to specific embodiments.

Implementation

As shown in FIGS. 1 and 2 , an ultra-small zoom lens includes, from an object side A1 to an image side A2, along an optical axis I, a first lens 1 to a fourth lens 4, an aperture 10, a fifth lens 5 to a ninth lens 9, a protective glass 100, and an imaging surface 1000; each of the first lens 1 to the ninth lens 9 includes an object-side surface facing the object side A1 and allowing imaging light to pass therethrough, and an image-side surface facing the image side A2 and allowing imaging light to pass therethrough.

The first lens 1 has a negative refractive power, the object side surface 11 of the first lens 1 is a convex surface, and the image side surface 12 of the first lens 1 is a concave surface; the second lens 2 has a negative refractive power, the object side surface 21 of the second lens 2 is a concave surface, and the image side surface 22 of the second lens 2 is a concave surface; the third lens 3 has a negative refractive power, the object side surface 31 of the third lens 3 is a convex surface, and the image side surface 32 of the third lens 3 is a convex surface; the fourth lens 4 has a positive refractive power, the object side surface 41 of the fourth lens 4 is a convex surface, and the image side surface 42 of the fourth lens 4 is a convex surface; the first lens 1 to the fourth lens 4 constitute a focusing lens group, which can move back and forth along the optical axis I relative to the aperture 10.

The fifth lens 5 has a positive refractive power, the object side surface 51 of the fifth lens 5 is a convex surface, and the image side surface 52 of the fifth lens 5 is a concave surface; the sixth lens 6 has a positive refractive power, the object side surface 61 of the sixth lens 6 is a convex surface, and the image side surface 62 of the sixth lens 6 is a convex surface; the seventh lens 7 has a negative refractive power, the object side surface 71 of the seventh lens 7 is a concave surface, and the image side surface 72 of the seventh lens 7 is a concave surface; the eighth lens 8 has a positive refractive power, the object side surface 81 of the eighth lens 8 is a convex surface, and the image side surface 82 of the eighth lens 8 is a convex surface; the ninth lens 9 has a negative refractive power, the object side surface 91 of the ninth lens 9 is a convex surface, and the image side surface 92 of the ninth lens 9 is a convex surface. The fifth lens 5 to the ninth lens 9 constitute a variable magnification lens group, which can move back and forth along the optical axis I relative to the aperture 10.

In this embodiment, a combination of seven pieces of glass and two pieces of plastic aspheric surfaces is used, including two groups of double cemented lenses, the first lens 1 to the fourth lens 4 are the front group of the lens, the fifth lens 5 to the ninth lens 9 are the rear group of the lens, the third and fourth lenses are cemented lenses, the sixth and seventh lenses are cemented lenses, the fifth and ninth lenses are plastic aspheric lenses, and the aperture 10 is located between the fourth lens and the fifth lens.

The detailed optical data of this specific embodiment at the shortest focal length (wide angle) are shown in Table 1-1.

Table 1-1 Detailed optical data of Example 1 at the shortest focal length

The detailed optical data of this specific embodiment at the longest focal length (telephoto) are shown in Table 1-2.

Table 1-2 Detailed optical data of Example 1 at the longest focal length

In this specific embodiment, the object-side surfaces 31 and 91 and the image-side surfaces 32 and 92 are defined according to the following aspheric curve formula:

in:

z: the depth of the aspherical surface (the vertical distance between the point on the aspherical surface that is y away from the optical axis and the tangent plane that is tangent to the vertex on the optical axis of the aspherical surface);

c: the curvature of the vertex of the aspherical surface (the vertex curvature);

K: Conic Constant;

radial distance;

r _n : normalization radius (NRADIUS);

u: r/r _n ;

a _m : is the m ^{th Q con coefficient} ;

_Qmcon ^: the ^mth order ^{Qcon polynomial} .

Please refer to Figures 3-14 for the resolution of this embodiment. Specifically, referring to Figures 3 and 5, it can be seen from the figures that the transmission function is well controlled, the resolution is low, and the resolution is low. In the visible light environment, at a wide angle, the MTF value of the spatial frequency of 200lp/mm is as low as 0.25, and at a telephoto, the MTF value of the spatial frequency of 200lp/mm is even lower than 0.1; in the infrared environment, at a spatial frequency of 200lp/mm, the MTF value is greater than 0.18, and there is little shooting noise; please refer to Figures 4 and 6 for the confocality of visible light and infrared 850nm, it can be seen that the confocality of visible light and infrared is good, at a wide angle, the defocus when the visible and infrared are switched is less than 4μm, and at a telephoto, the defocus when the visible and infrared are switched is less than 10μm; the lateral chromatic aberration diagram is detailed in Figures 7 and 13, it can be seen that the lateral chromatic aberration is less than ±0.005mm; the longitudinal aberration diagram is detailed in Figures 8 and 14, it can be seen that the horizontal axis chromatic aberration is small.

In this embodiment, TTL<32.3 mm, and the focal length range is between 3.15 mm and 8.0 mm.

Embodiment 2

As shown in FIGS. 15 and 16 , the surface profiles and refractive powers of the lenses of this embodiment and the first embodiment are the same, and only the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

The detailed optical data of this specific embodiment at the shortest focal length (wide angle) are shown in Table 2-1.

Table 2-1 Detailed optical data of Example 2 at the shortest focal length

The detailed optical data of this specific embodiment at the longest focal length (telephoto) are shown in Table 2-2.

Table 2-2 Detailed optical data of Example 2 at the longest focal length

Please refer to Figures 17-28 for the resolution of this specific embodiment. Specifically, referring to Figures 17 and 19, it can be seen from the figures that the transmission function is well controlled, the resolution is low, and the resolution is low. In the visible light environment, at a wide angle, the MTF value of the spatial frequency of 200lp/mm is as low as 0.25, and at a telephoto, the MTF value of the spatial frequency of 200lp/mm is even lower than 0.1; in the infrared environment, at a spatial frequency of 200lp/mm, the MTF value is greater than 0.18, and there is little shooting noise; please refer to Figures 18 and 20 for the confocality of visible light and infrared 850nm, it can be seen that the confocality of visible light and infrared is good, at a wide angle, the defocus when the visible and infrared are switched is less than 4μm, and at a telephoto, the defocus when the visible and infrared are switched is less than 10μm; the lateral chromatic aberration diagram is detailed in Figures 21 and 27, it can be seen that the lateral chromatic aberration is less than ±0.005mm; the longitudinal aberration diagram is detailed in Figures 22 and 28, it can be seen that the horizontal axis chromatic aberration is small.

In this embodiment, TTL<32.3 mm, and the focal length range is between 3.14 mm and 8.0 mm.

Embodiment 3

As shown in Figures 29 and 30, the surface profiles and refractive powers of the lenses of this embodiment and the first embodiment are the same, and only the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

The detailed optical data of this specific embodiment at the shortest focal length (wide angle) are shown in Table 3-1.

Table 3-1 Detailed optical data of Example 3 at the shortest focal length

The detailed optical data of this specific embodiment at the longest focal length (telephoto) are shown in Table 3-2.

Table 3-2 Detailed optical data of Example 3 at the longest focal length

Please refer to Figures 31-42 for the resolution of this specific embodiment. Specifically, referring to Figures 31 and 33, it can be seen from the figures that the transmission function is well controlled, the resolution is low, and the resolution is low. In the visible light environment, at a wide angle, the MTF value of the spatial frequency of 200lp/mm is as low as 0.28, and at a telephoto focus, the MTF value of the spatial frequency of 200lp/mm is even lower than 0.1; in the infrared environment, at a spatial frequency of 200lp/mm, the MTF value is greater than 0.18, and there is little shooting noise; please refer to Figures 32 and 34 for the confocality of visible light and infrared 850nm, it can be seen that the confocality of visible light and infrared is good, at a wide angle, the defocus when the visible and infrared are switched is less than 4μm, and at a telephoto focus, the defocus when the visible and infrared are switched is less than 10μm; the lateral chromatic aberration diagram is detailed in Figures 35 and 41, it can be seen that the lateral chromatic aberration is less than ±0.005mm; the longitudinal aberration diagram is detailed in Figures 36 and 42, it can be seen that the horizontal axis chromatic aberration is small.

In this embodiment, TTL<32.5mm, and the focal length range is between 3.14mm-8.0mm.

Embodiment 4

As shown in FIGS. 43 and 44 , the surface profile and refractive power of each lens in this embodiment are the same as those in the first embodiment, and only the optical parameters such as the radius of curvature of each lens surface and the lens thickness are different.

The detailed optical data of this specific embodiment at the shortest focal length (wide angle) are shown in Table 4-1.

Table 4-1 Detailed optical data of Example 4 at the shortest focal length

The detailed optical data of this specific embodiment at the longest focal length (telephoto) are shown in Table 4-2.

Table 4-2 Detailed optical data of the fourth embodiment at the longest focal length

Please refer to Figures 45-56 for the resolution of this specific embodiment. Specifically, refer to Figures 45 and 47. It can be seen from the figures that the transmission function is well controlled, the resolution is low, and the resolution is low. In the visible light environment, at a wide angle, the MTF value of the spatial frequency of 200lp/mm is as low as 0.28, and at a telephoto focus, the MTF value of the spatial frequency of 200lp/mm is even lower than 0.1; in the infrared environment, at a spatial frequency of 200lp/mm, the MTF value is greater than 0.18, and there is little shooting noise; please refer to Figures 46 and 48 for the confocality of visible light and infrared 850nm, it can be seen that the confocality of visible light and infrared is good, at a wide angle, the defocus when switching between visible and infrared is less than 4μm, and at a telephoto focus, the defocus when switching between visible and infrared is less than 10μm; the lateral chromatic aberration diagram is detailed in Figures 49 and 56, it can be seen that the lateral chromatic aberration is less than ±0.005mm; the longitudinal aberration diagram is detailed in Figures 50 and 56, it can be seen that the horizontal axis chromatic aberration is small.

In this embodiment, TTL<32.7 mm, and the focal length range is between 3.15 mm and 8.0 mm.

The above is only a preferred embodiment of the present invention. The present invention is not limited to the above implementation. As long as the technical effect of the present invention is achieved by the same means, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present disclosure shall be included in the scope of protection of the present disclosure. All should belong to the protection scope of the present invention. Within the protection scope of the present invention, its technical scheme and/or implementation method can have various modifications and changes.

Claims (6)

1. The ultra-small zoom lens is characterized by sequentially comprising a first lens, a second lens, a third lens, a fourth lens, a diaphragm, a fifth lens, a sixth lens, a seventh lens, an eighth lens and a ninth lens from an object side to an image side;

the first lens has negative refractive power and is provided with an object side surface facing to the object side and an image side surface facing to the image side, wherein the object side surface is a convex surface, and the image side surface is a concave surface;

the second lens has negative refractive power and is provided with an object side surface facing to the object side and an image side surface facing to the image side, wherein the object side surface is a concave surface, and the image side surface is a concave surface;

The third lens has negative refractive power and is provided with an object side surface facing to the object side and an image side surface facing to the image side, wherein the object side surface is a convex surface, and the image side surface is a concave surface;

the fourth lens has positive refractive index and is provided with an object side surface facing to the object side and an image side surface facing to the image side, wherein the object side surface is a convex surface;

The fifth lens has positive refractive index, and is provided with an object side surface facing to the object side and an image side surface facing to the image side, wherein the object side surface is a convex surface, and the image side surface is a concave surface;

The sixth lens element with positive refractive power has an object-side surface facing the object-side surface and an image-side surface facing the image-side surface, wherein the object-side surface is convex;

The seventh lens has negative refractive power and is provided with an object side surface facing to the object side and an image side surface facing to the image side, wherein the object side surface is a concave surface, and the image side surface is a concave surface;

the eighth lens has positive refractive index, and is provided with an object side surface facing to the object side and an image side surface facing to the image side, wherein the object side surface is a convex surface;

The ninth lens has negative refractive power and is provided with an object side surface facing to the object side and an image side surface facing to the image side, wherein the object side surface is a concave surface, and the image side surface is a convex surface;

The first to fourth lenses constitute a focus lens group; fifth to ninth constituent variable magnification lens groups; the third lens and the ninth lens are aspheric lenses;

The ultra-small zoom lens adopts a glass-plastic mixed 9-piece design, and the lens with refractive index is only nine pieces;

The ultra-small zoom lens satisfies the following conditions: and (3) vd4-vd3| >30 and vd7-vd6| >30, wherein vd3 and vd4 are the dispersion coefficients of the third lens and the fourth lens respectively, and vd6 and vd7 are the dispersion coefficients of the sixth lens and the seventh lens respectively.

2. The ultra-small zoom lens of claim 1, further satisfying: the third lens and the fourth lens are glued to each other.

3. The ultra-small zoom lens of claim 1, further satisfying: the sixth lens and the seventh lens are cemented with each other.

4. The ultra-small zoom lens of claim 1, further satisfying: the third lens and the ninth lens are 16-order even plastic aspheric designs.

5. The ultra-small zoom lens of claim 1, further satisfying: the first lens and the seventh lens are made of high refractive index materials, nd1=1.835 and nd7= 1.847, wherein nd1 is the refractive index of the first lens and nd7 is the refractive index of the seventh lens.

6. The ultra-small zoom lens of claim 1, further satisfying: the second, third and sixth lenses all use a material with a large dispersion coefficient, where vd2=58.35, vd3=59.51, vd6=51.16, vd2 being the dispersion coefficient of the second lens.