A high resolution oblique optical lens

Abstract

The application discloses a high-resolution oblique-axis optical lens, comprising, from the object side to the image side, 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, a ninth lens, a protective glass and an image sensor; the first lens is a filter; the second lens is a biconvex spherical lens with positive focal power; the third lens is a spherical lens with negative focal power; the fourth lens is a spherical lens with positive focal power; and the fifth lens is a biconcave spherical lens with negative focal power. The technical scheme balances and corrects optical aberrations of all levels by reasonably distributing the focal power of the lenses, reasonably matching the optical materials and shapes, and utilizes the cylindrical lens to correct astigmatism caused by the optical path of the meridian arc vector plane of the protective glass, so that the advantages of large target surface, low distortion, ultra-short object distance, high resolving power and the like of the lens are achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of optical lens, in particular to a high-resolution oblique-axis optical lens. BACKGROUND

[0002] In recent years, with the continuous upgrading of science and technology and consumption, industrial robots are widely used in various industries, and the demand for high-precision 3D topography detection is gradually increasing. And the application of 3D topography detection gradually tends to be high-precision and low-distortion actual demand, which requires oblique-axis lenses to have high resolution, low distortion optical performance, and the resolution of similar products on the market is poor, and the precision is low. SUMMARY

[0003] The present application aims to at least solve one of the technical problems existing in the prior art. To this end, the present application provides a high-resolution oblique-axis optical lens, which effectively solves the problems of poor resolution and low precision.

[0004] According to the high-resolution oblique-axis optical lens of the present application, the first lens, the second lens, the third lens, the fourth lens, the diaphragm, the fifth lens, the sixth lens, the seventh lens, the eighth lens, the ninth lens, the protective glass and the image sensor are arranged in order from the object side to the image side.

[0005] The first lens is a filter; the second lens is a double-convex spherical lens with positive focal power; the third lens is a spherical lens with negative focal power, the front surface from the object side to the image side is concave, and the rear surface is convex; the fourth lens is a spherical lens with positive focal power, the front surface from the object side to the image side is convex, and the rear surface is concave; the fifth lens is a double-concave spherical lens with negative focal power; the sixth lens is a double-convex spherical lens with positive focal power; the seventh lens is a double-concave spherical lens with negative focal power; the eighth lens is a double-convex spherical lens with positive focal power; and the ninth lens is a cylindrical lens with positive focal power.

[0006] According to the high-resolution oblique-axis optical lens of the present application, at least the following beneficial effects are achieved:

[0007] The present technical solution balances and corrects optical aberrations of each level by reasonably distributing the focal power of the lenses, reasonably matching the optical materials and shapes, and using a cylindrical lens to correct astigmatism caused by the optical path of the meridian arc plane of the protective glass, thereby achieving large target surface, low distortion, ultra-short object distance, high resolution and other advantages.

[0008] According to some embodiments of the present application, the focal length of the lenses of the high-resolution oblique-axis optical lens satisfies the following relationship:

[0009] 0.1≤f2 / f≤0.5;

[0010] -1.0

[0011] 0.3

[0012] -0.3

[0013] 0.2

[0014] -8.0

[0015] 0.8

[0016] 45

[0017] wherein, f is the effective focal length of the high resolution oblique axis optical lens, f2 is the focal length of the second lens, f3 is the focal length of the third lens, f4 is the focal length of the fourth lens, f5 is the focal length of the fifth lens, f6 is the focal length of the sixth lens, f7 is the focal length of the seventh lens, f8 is the focal length of the eighth lens, and fy9 is the focal length of the ninth lens in the plane in which the object plane and the optical axis form an angle.

[0018] According to some embodiments of the present application, the seventh lens and the eighth lens form a double cemented lens.

[0019] According to some embodiments of the present application, the focal length f78 of the double cemented lens satisfies the relationship: 0.4

[0020] According to some embodiments of the present application, one surface of the ninth lens is a plane and the other surface is a cylindrical surface, wherein the cylindrical surface of the ninth lens has the characteristic of spherical surface curvature in the plane in which the object plane and the optical axis form an angle and has the characteristic of a plane in the plane in which the object plane and the optical axis do not form an angle.

[0021] According to some embodiments of the present application, the size of the image sensor is 4 / 3 inch, the display resolution is 1920x1080, the pixel pitch is 10 um, and the Nyquist frequency is 50 lp / mm.

[0022] According to some embodiments of the present application, the effective focal length of the high resolution oblique axis optical lens is: EFL=64.85 mm, Fno=5.6.

[0023] According to some embodiments of the present application, the front surface or the rear surface of the first lens has a film layer with bandwidth filtering.

[0024] According to some embodiments of the present application, the optical axis of the high resolution oblique axis optical lens forms an angle θ=45° with the object plane.

[0025] According to some embodiments of the present application, the protective glass, the image sensor and the optical axis of the high-resolution oblique-axial optical lens form an angle ω = 39.6°.

[0026] Additional aspects and advantages of the present application will be made apparent from the following description, which, taken in conjunction with the accompanying drawings, that will be given for purely indicative and explanatory purposes. BRIEF DESCRIPTION OF DRAWINGS

[0027] The present application will be further described with reference to the accompanying drawings and examples, in which:

[0028] Figure 1 is a 2D diagram of an embodiment of the present application;

[0029] Figure 2 is a chromatic aberration, astigmatism field curvature, distortion map of an embodiment of the present application;

[0030] Figure 3 is a ray aberration map of an embodiment of the present application;

[0031] Figure 4 is an MTF map of an embodiment of the present application;

[0032] Figure 5 is a relative illuminance map of an embodiment of the present application.

[0033] LIST OF REFERENCE NUMBERS

[0034] First lens L1, second lens L2, third lens L3, fourth lens L4, stop STO, fifth lens L5, sixth lens L6, seventh lens L7, eighth lens L8, ninth lens L9, protective glass CG, image sensor IMA. DETAILED DESCRIPTION

[0035] Embodiments of the present application are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference signs represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by reference to the accompanying drawings are exemplary and are intended to explain the present application only, and should not be understood as limiting the present application.

[0036] In the description of the present application, it should be understood that the orientation description, such as the orientation or position relationship indicated by up, down, etc. is based on the orientation or position relationship shown in the drawings, and is only for the purpose of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be understood as limiting the present application.

[0037] In the description of the present application, more refers to more than two. If the first, the second is described for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features or implicitly indicating the sequence of indicated technical features.

[0038] In the description of the present application, unless otherwise explicitly limited, the words such as setting, installation, connection and the like should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meaning of the above words in the present application in combination with the specific content of the technical scheme.

[0039] Referring to Figure 1 As shown in the figure, a high-resolution oblique-axis optical lens of an embodiment of the present application comprises, arranged in order from the object side to the image side: a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a diaphragm STO, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, a ninth lens L9, a protective glass CG, and an image sensor IMA;

[0040] The first lens L1 is a filter that can filter out interfering light; the second lens L2 is a biconvex spherical lens with positive focal power; the third lens L3 is a spherical lens with negative focal power, the front surface from the object side to the image side is concave, and the rear surface is convex; the fourth lens L4 is a spherical lens with positive focal power, the front surface from the object side to the image side is convex, and the rear surface is concave; the fifth lens L5 is a biconcave spherical lens with negative focal power; the sixth lens L6 is a biconvex spherical lens with positive focal power; the seventh lens L7 is a biconcave spherical lens with negative focal power; the eighth lens L8 is a biconvex spherical lens with positive focal power; and the ninth lens L9 is a cylindrical lens with positive focal power, which is used to correct the astigmatism caused by the optical path of the meridional arc vector plane of the protective glass.

[0041] As can be seen from the above, the technical scheme balances and corrects the optical aberration of each level by reasonably allocating the focal power of the lenses, matching the optical materials and shapes, and using a cylindrical lens to solve the astigmatism problem of the oblique-axis lens, thereby realizing the advantages of large target surface, low distortion, ultra-short object distance, high resolution and the like of the lens.

[0042] In some embodiments of the present application, the focal length of the lenses of the high-resolution oblique-axis optical lens satisfies the following relationship:

[0043] 0.1≤f2 / f≤0.5;

[0044] -1.0≤f3 / f≤-0.4;

[0045] 0.3≤f4 / f≤0.8;

[0046] -0.3≤f5 / f≤-0.1;

[0047] 0.2≤f6 / f≤0.5;

[0048] -8.0≤f7 / f≤-4.0;

[0049] 0.8≤f8 / f≤1.4;

[0050] 45≤fy9 / f≤60;

[0051] Wherein, f is the effective focal length of the high resolution oblique optical lens, f2 is the focal length of the second lens L2, f3 is the focal length of the third lens L3, f4 is the focal length of the fourth lens L4, f5 is the focal length of the fifth lens L5, f6 is the focal length of the sixth lens L6, f7 is the focal length of the seventh lens L7, f8 is the focal length of the eighth lens L8, and fy9 is the focal length of the ninth lens L9 in the plane with the angle between the object plane and the optical axis. It should be pointed out that the above focal length interval is only the protection range of the technical solution, and one of the point values is not limited. The following table is an embodiment parameter of the technical solution:

[0052]

[0053] Table 1

[0054] In some embodiments of the present application, the seventh lens L7 and the eighth lens L8 form a positive power double cemented lens, which can effectively eliminate the chromatic aberration of the front group of lenses.

[0055] Further, in some embodiments of the present application, the focal length f78 of the double cemented lens satisfies the relationship: 0.4≤f78 / f≤1.0; wherein f is the effective focal length of the high resolution oblique optical lens.

[0056] In some embodiments of the present application, one surface of the ninth lens L9 is a plane and the other surface is a cylindrical surface, wherein the cylindrical surface of the ninth lens L9 has the characteristics of spherical surface curvature in the plane with the angle between the object plane and the optical axis, and has the characteristics of a plane in the plane without the angle between the object plane and the optical axis, which can effectively correct the astigmatism caused by the optical path of the meridian arc plane of the protective glass.

[0057] In some embodiments of the present application, the size of the image sensor IMA is 4 / 3 inch, the display resolution is 1920x1080, the pixel pitch is 10um, and the Nyquist frequency is 50lp / mm. It should be pointed out that it is not limited to a certain type of sensor (image sensor, such as CMOS, CCD, etc.).

[0058] Specifically, in some embodiments of the present invention, the effective focal length of the high-resolution oblique-axis optical lens is: EFL=64.85mm, Fno=5.6, and the TV distortion is less than 0.3% in oblique-axis mode. During focusing, the entire lens assembly moves left and right along the optical axis (i.e., optical back focal length changes).

[0059] In some embodiments of the present invention, the front or rear surface of the first lens L1 has a bandwidth filtering film. The first lens L1 is a parallel planar filter with a certain thickness, and its optical surface is coated with different bandwidth films depending on whether it is day or night. The filter can be an infrared cutoff or absorption filter, or a full-transmission spectral filter, which can filter out interfering light and enable the image sensor IMA to obtain the best imaging effect.

[0060] In some embodiments of the present invention, the optical axis of the high-resolution oblique-axis optical lens forms an angle θ=45° with the object plane, and the protective glass CG, the image sensor IMA, and the optical axis of the high-resolution oblique-axis optical lens form an angle ω=39.6°. At this time, the lens principal plane, the projection object plane, and the imaging plane intersect at a line, satisfying Scherm's law and achieving clear imaging of the entire oblique object plane lens field of view (FOV).

[0061] like Figures 2 to 5 The image shown is an optical evaluation diagram of an embodiment of the present invention. Figure 2 The image shown is a spherical aberration field curve from an embodiment of the present invention. It can be seen that the chromatic aberration along the red and green light axes is small. Since the optical distortion of the oblique axis optical system is not considered, the TV distortion is calculated to be Dv=0.28%. The h oblique axis direction is not considered, resulting in a small degree of image distortion. Figure 3 The light aberration diagram of this embodiment of the invention shows that the aberrations are well balanced and corrected, the magnification color difference is about half a pixel, and the color difference effect of the actual shooting picture is good. Figure 4 The MTF plot of this embodiment of the invention can achieve a global MTF greater than 0.35 at 100 lp / mm. Figure 5 The relative illuminance curve of this embodiment of the invention shows that the ratio of the brightness of the peripheral area to the brightness of the central area is greater than 90%, indicating good uniformity of brightness in the image.

[0062] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A high-resolution oblique-axis optical lens, characterized in that, The following components are arranged sequentially from the object side to the image side: first lens (L1), second lens (L2), third lens (L3), fourth lens (L4), aperture stop (STO), fifth lens (L5), sixth lens (L6), seventh lens (L7), eighth lens (L8), ninth lens (L9), protective glass (CG), and image sensor (IMA). The first lens (L1) is a filter; the second lens (L2) is a biconvex spherical lens with positive optical power; the third lens (L3) is a spherical lens with negative optical power, with a concave front surface and a convex rear surface from the object side to the image side; the fourth lens (L4) is a spherical lens with positive optical power, with a convex front surface and a concave rear surface from the object side to the image side; the fifth lens (L5) is a biconcave spherical lens with negative optical power; the sixth lens (L6) is a biconvex spherical lens with positive optical power; the seventh lens (L7) is a biconcave spherical lens with negative optical power; the eighth lens (L8) is a biconvex spherical lens with positive optical power; and the ninth lens (L9) is a cylindrical lens with positive optical power. The focal lengths of the lenses in the high-resolution oblique-axis optical lens satisfy the following relationship: 0.1 ≤ f² / f ≤ 0.5; -1.0≤f3 / f≤-0.4; 0.3≤f4 / f≤0.8; -0.3≤f5 / f≤-0.1; 0.2≤f6 / f≤0.5; -8.0≤f7 / f≤-4.0; 0.8 ≤ f8 / f ≤ 1.4; 45≤fy9 / f≤60; Wherein, f is the effective focal length of the high-resolution oblique-axis optical lens, f2 is the focal length of the second lens (L2), f3 is the focal length of the third lens (L3), f4 is the focal length of the fourth lens (L4), f5 is the focal length of the fifth lens (L5), f6 is the focal length of the sixth lens (L6), f7 is the focal length of the seventh lens (L7), f8 is the focal length of the eighth lens (L8), and fy9 is the focal length of the ninth lens (L9) in the plane where the object plane forms an angle with the optical axis.

2. A high-resolution oblique-axis optical lens according to claim 1, characterized in that, The seventh lens (L7) and the eighth lens (L8) together form a cemented doublet lens.

3. A high-resolution oblique-axis optical lens according to claim 2, characterized in that, The focal length f78 of the cemented doublet lens satisfies the following relationship: 0.4≤f78 / f≤1.0; where f is the effective focal length of the high-resolution oblique-axis optical lens.

4. A high-resolution oblique-axis optical lens according to claim 1, characterized in that: The ninth lens (L9) has one surface as a plane and the other surface as a cylinder. The cylinder of the ninth lens (L9) has the characteristics of spherical curvature in a plane where there is an angle between the object plane and the optical axis, and the characteristics of a plane in a plane where there is no angle between the object plane and the optical axis.

5. A high-resolution oblique-axis optical lens according to claim 1, characterized in that: The image sensor (IMA) is 4 / 3 inch in size, has a display resolution of 1920×1080, a pixel pitch of 10µm, and a Nyquist frequency of 50lp / mm.

6. A high-resolution oblique-axis optical lens according to claim 1, characterized in that: The effective focal length of the high-resolution oblique-axis optical lens is: EFL=64.85mm, Fno=5.

6.

7. A high-resolution oblique-axis optical lens according to claim 1, characterized in that: The front or rear surface of the first lens (L1) has a bandwidth filtering film.

8. A high-resolution oblique-axis optical lens according to claim 1, characterized in that: The optical axis of the high-resolution oblique-axis optical lens forms an angle θ=45° with the object plane.

9. A high-resolution oblique-axis optical lens according to claim 1, characterized in that: The protective glass (CG), the image sensor (IMA), and the optical axis of the high-resolution oblique-axis optical lens form an angle ω=39.6°.

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