Wide-angle optical system suitable for front binocular camera module and working method thereof

Abstract

The present application relates to a kind of wide-angle optical system suitable for front binocular camera module and its working method: optical system is sequentially arranged by first lens, second lens, third lens, diaphragm, fourth lens, fifth lens and sixth lens along the direction of light incidence, fourth lens and fifth lens are glued into glued lens group, the imaging angle of the lens of the present application to object is greater than 120 degrees, while having higher imaging definition, large light aperture, lower tolerance sensitivity and better high-low temperature stability and other advantages, at the same time, vehicle front scene can be more comprehensively monitored, by the reasonable collocation of each optical lens, so that system structure is compact and reasonable, reduce overall volume, easy to assemble, tolerance sensitivity is low, more suitable for large-scale high yield production, corrects each axial chromatic aberration, sagittal chromatic aberration and high-order chromatic aberration, ensure that imaging system can also have higher imaging quality when in large angle.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of wide-angle optical system suitable for front binocular camera module and its working method. BACKGROUND

[0002] Camera sensor ranging is to use camera to shoot the image of the object in front, analyze the image with detected object by some specific image algorithm, and finally obtain the depth distance of obstacle information.Compared with other ranging sensor technologies, the camera sensor technology is more mature, firstly, the whole process algorithm cost is low, and it does not need to emit signal, so the interference (between vehicles, between electronic devices) to its ranging is not big.

[0003] The vehicle-mounted binocular camera module is composed of two binocular stereo cameras, the distance between the optical axes of the lenses is about 22-25 cm, the effective detection distance is about 120 mm, and the field of view angle of the camera is about 50°.The binocular camera can complete 3D stereo recognition function, can complete target tracking, position prediction and realize target speed detection with millimeter wave radar.Currently, the main problems of vehicle-mounted binocular camera module are small field of view angle, high cost, complex system, and difficult product miniaturization. SUMMARY

[0004] In view of the deficiencies of the prior art, the present application provides a kind of wide-angle optical system suitable for front binocular camera module.In the realization of wide-angle 120° clear imaging, it has smaller size, higher environmental stability.

[0005] The technical problem solved by the present application is solved by the following scheme: a kind of wide-angle optical system suitable for front binocular camera module: the optical system is composed of first lens, second lens, third lens, diaphragm, fourth lens, fifth lens and sixth lens arranged in order along the light incidence direction, the fourth lens and the fifth lens are glued into a glued lens group.

[0006] Further, the first lens is a meniscus concave negative lens, the object side is convex, and the image side is concave;the second lens is a double concave negative lens, the object side is concave, and the image side is concave;the third lens is a double convex positive lens, the object side is convex, and the image side is convex;the fourth lens is a meniscus concave negative lens, the object side is convex, and the image side is concave;the fifth lens is a double convex positive lens, the object side is convex, and the image side is convex;the sixth lens is a double convex positive lens, the object side is convex, and the image side is convex.

[0007] Further, the second lens, the third lens, the fourth lens and the fifth lens are glass spherical lenses, and the first lens and the sixth lens are glass aspherical lenses.

[0008] Further, the air gap between the first lens and the second lens is 2.0-2.5mm; the air gap between the second lens and the third lens is 3.0-3.5mm; the air gap between the third lens and the diaphragm is 0.5-1.0mm; the air gap between the diaphragm and the fourth lens is 0.1-0.5mm; and the air gap between the fifth lens and the sixth lens is 0.1-0.5mm.

[0009] Further, the first lens satisfies the relationship: 1.6≤N d ≤1.9, V d ≤50.0; the second lens satisfies the relationship: 1.4≤N d ≤1.7, V d ≥50.0; the third lens satisfies the relationship: 1.7≤N d ≤2.0, V d ≤50.0; the fourth lens satisfies the relationship: 1.7≤N d ≤2.0, V d ≤50.0; the fifth lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≥50.0; and the sixth lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≥50.0; wherein N d is the refractive index, and V d is the Abbe number.

[0010] Further, the focal length of the lens is f, and the focal lengths of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens are f1, f2, f3, f4, f5, and f6, respectively, wherein f1, f2, f3, f4, f5, and f6 satisfy the following ratios: -2.0

[0011] Further, the aspherical lens curve equation expression of the first lens and the sixth lens is:

[0012]

[0013] wherein Z is the sagittal height of the aspherical surface at a height of h along the optical axis from the vertex of the aspherical surface; c is the paraxial curvature of the aspherical surface; k is the conic constant; and α1, α2, α3, α4, α5, α6, α7, and α8 are high-order coefficients.

[0014] Further, the optical total length TTL of the optical system and the focal length f of the optical system satisfy: TTL / f≤6.0, and the image height H of the optical system and the focal length f of the optical system satisfy: H / f≤1.0.

[0015] Further, the rear side of the sixth lens is provided with a filter.

[0016] A working method of a wide-angle optical system suitable for a front binocular camera module: when light is incident, the light path sequentially enters a first lens, a second lens, a third lens, a diaphragm, a fourth lens, a fifth lens, a sixth lens, and finally forms an image on an image plane.

[0017] Compared with the prior art, the present application has the following beneficial effects:

[0018] 1. The lens has an imaging angle of more than 120 degrees for an object, and has the advantages of high imaging clarity, large light aperture, low tolerance sensitivity, and good high and low temperature stability, etc. At the same time, the front view of the vehicle can be monitored more comprehensively.

[0019] 2. By reasonably matching each optical lens, the system structure is compact and reasonable, the overall volume is reduced, easy to assemble, the tolerance sensitivity is low, and it is more suitable for large-scale high-yield production.

[0020] 3. The all-glass lens structure can make good compensation for the focal plane displacement at high and low temperatures, and has high adaptability to complex environments.

[0021] 4. The axial chromatic aberration, sagittal chromatic aberration and high-order chromatic aberration are corrected, so that the imaging system can also have high imaging quality at a large angle. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is the optical structure schematic diagram of the present application;

[0023] Figure 2 is the full working waveband axial chromatic aberration diagram of the present application;

[0024] Figure 3 is the full working waveband sagittal chromatic aberration diagram of the present application;

[0025] Figure 4 is the full working waveband field curvature distortion diagram of the present application.

[0026] In the figure: STO-diaphragm; L1-first lens; L2-second lens; L3-third lens; L4-fourth lens; L5-fifth lens; L6-sixth lens; L7-equivalent glass flat plate; L8-equivalent glass flat plate; IMA-imaging plane. DETAILED DESCRIPTION

[0027] The application will be further described below in conjunction with the drawings and specific embodiments.

[0028] As Figure 1 shown, a wide-angle optical system suitable for a front binocular camera module: the optical system is composed of a first lens, a second lens, a third lens, a diaphragm, a fourth lens, a fifth lens and a sixth lens arranged in sequence along the light incident direction, the fourth lens and the fifth lens are glued into a glued lens group.

[0029] In the embodiment, the first lens is a meniscus concave negative lens, the object side is convex, and the image side is concave; the second lens is a double-concave negative lens, the object side is concave, and the image side is concave; the third lens is a double-convex positive lens, the object side is convex, and the image side is convex; the fourth lens is a meniscus concave negative lens, the object side is convex, and the image side is concave; the fifth lens is a double-convex positive lens, the object side is convex, and the image side is convex; the sixth lens is a double-convex positive lens, the object side is convex, and the image side is convex.

[0030] In the embodiment, more specifically, the first lens is a glass aspheric lens with negative focal power, which adjusts the large-angle light and reduces the distortion of the optical system. The fourth lens and the fifth lens form an achromatic double-glued lens. Reasonable lens matching makes the optical system achieve small size, super wide angle, large aperture, day and night confocal, low temperature drift design, and good correction of on-axis and off-axis aberrations, and has good imaging quality, as Figures 2 to 4 shown.

[0031] In the embodiment, the second lens, the third lens, the fourth lens and the fifth lens are glass spherical lenses, and the first lens and the sixth lens are glass aspheric lenses.

[0032] In the embodiment, the air gap between the first lens and the second lens is 2.0-2.5mm; the air gap between the second lens and the third lens is 3.0-3.5mm; the air gap between the third lens and the diaphragm is 0.5-1.0mm; the air gap between the diaphragm and the fourth lens is 0.1-0.5mm; and the air gap between the fifth lens and the sixth lens is 0.1-0.5mm.

[0033] In the embodiment, the first lens satisfies the relationship: 1.6≤N d ≤1.9, V d ≤50.0; the second lens satisfies the relationship: 1.4≤N d ≤1.7, V d ≥50.0; and the third lens satisfies the relationship: 1.7≤N d ≤2.0, V d≤ 50.0; the fourth lens satisfies the relationship: 1.7 ≤ N d ≤ 2.0, V d ≤ 50.0; the fifth lens satisfies the relationship: 1.5 ≤ N d ≤ 1.8, V d ≥ 50.0; the sixth lens satisfies the relationship: 1.5 ≤ N d ≤ 1.8, V d ≥ 50.0; wherein N d is the refractive index, V d is the Abbe number.

[0034] In the embodiment, the focal length of the lens is f, and the focal lengths of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens are f1, f2, f3, f4, f5, and f6 respectively, wherein f1, f2, f3, f4, f5, and f6 satisfy the following ratios: -2.0 < f1 / f < -1.0, -3.0 < f2 / f < -2.0, 1.0 < f3 / f < 2.0, 2.0 < f4 / f < -1.0, 1.0 < f5 / f < 2.0, and 2.0 < f6 / f < 3.0.

[0035] In the embodiment, the aspherical lens curve equation expression of the first lens and the sixth lens is:

[0036]

[0037] wherein Z is the sagittal height of the asphere at a height of h along the optical axis from the vertex of the asphere; c is the paraxial curvature of the asphere; k is the conic constant; α1, α2, α3, α4, α5, α6, α7, and α8 are high-order coefficients.

[0038] In the embodiment, the total optical length TTL of the optical system and the focal length f of the optical system satisfy: TTL / f ≤ 6.0.

[0039] In the embodiment, the F number of the optical system is ≤1.5.

[0040] In the embodiment, the rear side of the sixth lens is provided with a filter.

[0041] In the embodiment, the image height H of the optical system and the focal length f of the optical system satisfy: H / f ≤ 1.0.

[0042] The technical indicators achieved by the optical system in the embodiment are as follows:

[0043] (1) focal length: 5.0 ≤ EFFL ≤ 6.0 mm;

[0044] (2) aperture F ≤ 1.5;

[0045] (3) field of view: 2w≥120°;

[0046] (4) working waveband: visible light waveband.

[0047] To realize the above design parameters, the specific design of the optical system of the embodiment is shown in the following table:

[0048]

[0049]

[0050] The aspheric coefficients of each aspheric lens of the optical system of the embodiment are shown in the following table:

[0051]

[0052] A working method of a wide-angle optical system suitable for a front binocular camera module: when light is incident, the light path sequentially enters a first lens, a second lens, a third lens, a diaphragm, a fourth lens, a fifth lens, a sixth lens, and finally forms an image on an image plane.

[0053] The optical system of the embodiment, by reasonably allocating the optical power, surface shape, central thickness of each lens, and axial distance between each lens, etc., while meeting the requirements of the super-wide-angle imaging performance of the lens, reduces the total length of the lens and the radial size of each lens, and achieves the miniaturization of the lens group.

[0054] Any technical solution disclosed in the present application, unless otherwise stated, if it discloses a numerical range, the disclosed numerical range is a preferred numerical range, any person skilled in the art should understand that the preferred numerical range is only one of the many implementable numerical values with more obvious technical effects or representative values. Because there are too many values, it is impossible to enumerate them all, so the present application discloses some values to illustrate the technical solutions of the present application, and the above-mentioned enumerated values should not constitute a limitation on the protection scope of the present application.

[0055] If the words "first", "second", etc. are used to limit the components in this document, those skilled in the art should know that the use of "first", "second" is only for the convenience of describing the components to be distinguished, and the above words have no special meaning unless otherwise stated.

[0056] If the present application discloses or relates to mutually fixedly connected parts or structural members, unless otherwise stated, the fixed connection can be understood as: detachably fixedly connected (for example, connected using bolts or screws), and can also be understood as: non-detachable fixed connection (for example, riveting, welding), of course, the mutually fixed connection can also be replaced by an integral structure (for example, manufactured by integral forming using casting process) (obviously, integral forming process cannot be used).

[0057] In addition, the above-mentioned application discloses any technical solution applied to indicate the position relationship, such as "vertical", "horizontal", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc. The orientation or position relationship is based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the patent, and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation, therefore cannot be understood as a limitation of the patent, and the above-mentioned application discloses any technical solution applied to indicate the shape, unless otherwise stated, the meaning includes the shape similar, similar or close to the shape.

[0058] Any component provided by the present application can be assembled from multiple individual components, or can be a single component manufactured by integral forming process.

[0059] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application and not to limit them; although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the specific embodiments of the present application can be modified or some technical features can be replaced by equivalent; without departing from the spirit of the technical scheme of the present application, it should be understood that all should be covered in the technical scheme range of the present application claimed by the present application.

Claims

1. A wide-angle optical system suitable for a front dual-camera module, characterized in that: The optical system is composed of a first lens, a second lens, a third lens, a diaphragm, a fourth lens, a fifth lens and a sixth lens arranged in sequence along the light ray incident direction, the fourth lens and the fifth lens are cemented into a cemented lens group; the first lens is a meniscus concave negative lens, the object side surface is a convex surface, and the image side surface is a concave surface; the second lens is a double concave negative lens, the object side surface is a concave surface, and the image side surface is a concave surface; the third lens is a double convex positive lens, the object side surface is a convex surface, and the image side surface is a convex surface; the fourth lens is a meniscus concave negative lens, the object side surface is a convex surface, and the image side surface is a concave surface; the fifth lens is a double convex positive lens, the object side surface is a convex surface, and the image side surface is a convex surface; the sixth lens is a double convex positive lens, the object side surface is a convex surface, and the image side surface is a convex surface; The second lens, the third lens, the fourth lens and the fifth lens are glass spherical lenses, and the first lens and the sixth lens are glass aspherical lenses; The air gap between the first lens and the second lens is 2.0-2.5 mm; the air gap between the second lens and the third lens is 3.0-3.5 mm; the air gap between the third lens and the diaphragm is 0.5-1.0 mm; the air gap between the diaphragm and the fourth lens is 0.1-0.5 mm; and the air gap between the fifth lens and the sixth lens is 0.1-0.5 mm.

2. The wide-angle optical system according to claim 1, characterized by: the first lens satisfies the relationship: 1.6 ≤ N d ≤ 1.9, V d ≤ 50.0; the second lens satisfies the relationship: 1.4 ≤ N d ≤ 1.7, V d ≥ 50.0; the third lens satisfies the relationship: 1.7 ≤ N d ≤ 2.0, V d ≤ 50.0; the fourth lens satisfies the relationship: 1.7 ≤ N d ≤ 2.0, V d ≤ 50.0; the fifth lens satisfies the relationship: 1.5 ≤ N d ≤ 1.8, V d ≥ 50.0; the sixth lens satisfies the relationship: 1.5 ≤ N d ≤ 1.8, V d ≥ 50.0; wherein N d is the refractive index, and V d is the Abbe number.

3. The wide-angle optical system according to claim 1, characterized by: The focal length of the optical system is f, and the focal lengths of the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are f1, f2, f3, f4, f5 and f6 respectively, wherein f1, f2, f3, f4, f5 and f6 satisfy the following ratios: -2.0 < f1 / f < -1.0, -3.0 < f2 / f < -2.0, 1.0 < f3 / f < 2.0, -2.0 < f4 / f < -1.0, 1.0 < f5 / f < 2.0, and 2.0 < f6 / f < 3.

0.

4. The wide-angle optical system according to claim 1, characterized by: The aspherical lens curve equation expression of the first lens and the sixth lens is: wherein Z is the sagittal height of the aspherical surface at a height of h along the optical axis; c is the paraxial curvature of the aspherical surface; k is the conic constant; and α1, α2, α3, α4, α5, α6, α7 and α8 are high-order coefficients.

5. The wide-angle optical system according to claim 1, characterized by: The total optical length TTL of the optical system and the focal length f of the optical system satisfy TTL / f≤6.0, and the image height H of the optical system and the focal length f of the optical system satisfy H / f≤1.

0.

6. The wide-angle optical system according to claim 1, characterized by: The rear side of the sixth lens is provided with a filter.

7. A working method of a wide-angle optical system suitable for a front dual-camera module, using the optical system according to any one of claims 1-6, characterized in that: When the light ray is incident, the light path sequentially enters the first lens, the second lens, the third lens, the diaphragm, the fourth lens, the fifth lens and the sixth lens, and finally forms an image on the image plane.

Images