Small volume and low cost vehicle-mounted OMS lens and imaging method thereof

Abstract

The present application relates to the technical field of lens, especially to a small volume and low cost vehicle-mounted OMS lens and an imaging method thereof, the optical system of the lens is composed of a first lens, a second lens, a third lens, a fourth lens, a diaphragm, a fifth lens, a sixth lens and a seventh lens arranged in sequence from left to right along the light incident path; without considering the reverse bending caused by the aspherical surface coefficient, the first lens is a meniscus concave negative lens, the second lens is a meniscus concave negative lens, the third lens is a meniscus convex positive lens, the fourth lens is a double convex positive lens, the fifth lens is a double concave negative lens, the sixth lens is a double convex positive lens, and the seventh lens is a meniscus convex positive lens, wherein the fifth lens and the sixth lens form a cemented lens group, and the second lens, the third lens, the fifth lens, the sixth lens and the seventh lens are aspherical surface lenses. The lens can realize clear imaging of a larger field of view, and has a smaller volume and a lower cost.

Description

Technical Field

[0001] The present invention relates to the field of lens technology, and in particular to a small-volume, low-cost vehicle-mounted OMS lens and an imaging method thereof. Background Art

[0002] The smart cockpit, also known as the intelligent occupant monitoring system (OMS), is designed to ensure not only driver safety but also the safety and ride experience of passengers. Beyond cabin safety, the passenger experience is also a key component of the smart cockpit's purpose. By moving away from cumbersome mechanical cockpit controls and transitioning to human-machine interaction integrated with computer vision, passengers simply make gestures, and the cockpit system uses sensors to identify their intentions and activate the appropriate functions, significantly enhancing the passenger experience.

[0003] To adapt to complex driving environments and the OMS's requirements for a larger field of view and higher optical performance, such as higher resolution, the current market mostly adopts an all-glass structure and is relatively large in size, which is not conducive to system integration and cost reduction. Summary of the Invention

[0004] The object of the present invention is to provide a small-volume and low-cost vehicle-mounted OMS lens and an imaging method thereof, wherein the lens can achieve clear imaging with a larger field of view while having a small volume and low cost.

[0005] The technical solution of the present invention is: a small-volume, low-cost vehicle-mounted OMS lens, the optical system of the lens consists of a first lens, a second lens, a third lens, a fourth lens, an aperture, a fifth lens, a sixth lens and a seventh lens arranged in sequence from left to right along the incident light path of the light; without considering the backcurvature caused by the aspheric coefficient, the first lens is a meniscus concave negative lens, the second lens is a meniscus concave negative lens, the third lens is a meniscus convex positive lens, the fourth lens is a biconvex positive lens, the fifth lens is a biconcave negative lens, the sixth lens is a biconvex positive lens, and the seventh lens is a meniscus convex positive lens, wherein the fifth lens and the sixth lens form a cemented lens group, and the second lens, the third lens, the fifth lens, the sixth lens and the seventh lens are aspheric lenses.

[0006] Furthermore, the object-side surface of the first lens is convex, and the image-side surface is concave; the object-side surface of the second lens is convex, and the image-side surface is concave; the object-side surface of the third lens is convex, and the image-side surface is concave; the object-side surface of the fourth lens is convex, and the image-side surface is convex; the object-side surface of the fifth lens is concave, and the image-side surface is concave; the object-side surface of the sixth lens is convex, and the image-side surface is convex; the object-side surface of the seventh lens is convex, and the image-side surface is concave.

[0007] Furthermore, the first lens and the fourth lens are both glass spherical lenses, and the second lens, the third lens, the fifth lens, the sixth lens and the seventh lens are plastic aspherical lenses.

[0008] Furthermore, the air gap between the first lens and the second lens is 1.5-2.0 mm; the air gap between the second lens and the third lens is 0.0-0.5 mm; the air gap between the third lens and the fourth lens is 0.0-0.5 mm; the air gap between the fourth lens and the aperture is 0.0--0.5 mm; the air gap between the aperture and the fifth lens is 0.0-0.5 mm; and the air gap between the sixth lens and the seventh lens is 0.0-0.5 mm.

[0009] Furthermore, the focal length of the optical system is The focal lengths of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens are 、 、 、 、 、 、 ,in 、 、 、 、 、 、 and Meet the following ratio: -3.0< / <-2.0, -3.0< / <-2.0, 4.0< / <5.0, 1.0< / <2.0, -1.0< / <0.0, 1.0< / <2.0,62.0< / <63.0.

[0010] Furthermore, the first lens satisfies the relationship: 2.0≤ ≤2.5, ≤50.0; the second lens satisfies the relationship: 1.5≤ ≤1.8, ≥50.0; the third lens satisfies the relationship: 1.5≤ ≤2.0, ≤50.0; the fourth lens satisfies the relationship: 2.0≤ ≤2.5, ≤50.0; the fifth lens satisfies the relationship: 1.5≤ ≤2.0, ≤50.0; the sixth lens satisfies the relationship: 1.5≤ ≤1.8, ≥50.0; the seventh lens satisfies the relationship: 1.5≤ ≤1.8, ≥50.0; among them is the refractive index, is the Abbe constant.

[0011] Furthermore, the aspheric curve equation of the aspheric lens is expressed as:

[0012]

[0013] Where Z is the height of the aspheric surface from the vertex of the aspheric surface at a height of h along the optical axis; c is the paraxial curvature of the aspheric surface; k is the conic constant; All are high-order coefficients.

[0014] Furthermore, the total optical length TTL of the optical system and the focal length f of the optical system satisfy the following conditions: TTL / f≤8; and the F number of the optical system≤2.4.

[0015] Furthermore, the image height H of the optical system and the focal length f of the optical system satisfy: H / f≥1.0.

[0016] An imaging method for a small-volume, low-cost vehicle-mounted OMS lens includes a small-volume, low-cost vehicle-mounted OMS lens. Light enters a first lens, a second lens, a third lens, a fourth lens, an aperture, a fifth lens, a sixth lens, a seventh lens, and a first equivalent glass plate and a second equivalent glass plate sequentially arranged behind the seventh lens from left to right, and then forms an image on an imaging surface.

[0017] Compared with the prior art, the present invention has the following advantages:

[0018] 1. The lens has an imaging angle of greater than 180 degrees and has the advantages of high imaging clarity, low tolerance sensitivity, and good high and low temperature stability. At the same time, it can more comprehensively observe the passengers in the car;

[0019] 2. By properly matching the optical lenses, the system structure becomes more compact and reasonable to reduce the volume. At the same time, it has low tolerance sensitivity and is easy to assemble, making it more suitable for large-scale high-yield production;

[0020] 3. Using two glass lenses with five plastic lenses, it can adapt to the environment while reducing costs;

[0021] 4. Able to make good compensation for focal plane displacement at high and low temperatures, and have adaptability to complex environments;

[0022] 5. The axial chromatic aberration, vertical chromatic aberration and high-order chromatic aberration are corrected to ensure that the imaging system can have high imaging quality even at large angles. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of the optical structure of the present invention;

[0024] Figure 2 This is the full working band axial chromatic aberration diagram of the present invention;

[0025] Figure 3 This is the vertical axis chromatic aberration diagram of the full working band of the present invention;

[0026] Figure 4 This is the field curvature distortion diagram of the full working band of the present invention;

[0027] In the figure: L1-first lens; L2-second lens; L3-third lens; L4-fourth lens; STO-aperture; L5-fifth lens; L6-sixth lens; L7-seventh lens; L8-first equivalent glass plate; L9-second equivalent glass plate; IMA-imaging surface. DETAILED DESCRIPTION

[0028] To make the above features and advantages of the present invention more clearly understood, embodiments are given below with reference to the accompanying drawings for detailed description, but the present invention is not limited thereto.

[0029] refer to Figures 1 to 4

[0030] A small, low-cost, automotive OMS lens. The lens' optical system consists of a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, an aperture STO, a fifth lens L5, a sixth lens L6, and a seventh lens L7, arranged sequentially from the object side to the image side. Without considering the backcurvature caused by aspheric coefficients, the first lens is a meniscus concave negative lens, the second lens is a meniscus concave negative lens, the third lens is a meniscus convex positive lens, the fourth lens is a biconvex positive lens, the fifth lens is a biconcave negative lens, the sixth lens is a biconvex positive lens, and the seventh lens is a meniscus convex positive lens. The fifth and sixth lenses form an achromatic doublet, and the second, third, fifth, sixth, and seventh lenses are aspheric lenses. Because the first and second lenses both have negative optical power, they can adjust large-angle light. The plastic aspheric lens also reduces optical system distortion. Through reasonable lens matching, the optical system achieves ultra-wide angle, large aperture, day and night confocal, low temperature drift design, and at the same time, it has good correction for on-axis and off-axis aberrations, with good imaging quality.

[0031] In this embodiment, the object-side surface of the first lens is convex, and the image-side surface is concave; the object-side surface of the second lens is convex, and the image-side surface is concave; the object-side surface of the third lens is convex, and the image-side surface is concave; the object-side surface of the fourth lens is convex, and the image-side surface is convex; the object-side surface of the fifth lens is concave, and the image-side surface is concave; the object-side surface of the sixth lens is convex, and the image-side surface is convex; and the object-side surface of the seventh lens is convex, and the image-side surface is concave.

[0032] In this embodiment, the first lens and the fourth lens are both glass spherical lenses, and the second lens, the third lens, the fifth lens, the sixth lens, and the seventh lens are plastic aspherical lenses.

[0033] In this embodiment, a first equivalent glass plate L8 and a second equivalent glass plate L9 are sequentially disposed between the seventh lens and the imaging plane.

[0034] In this embodiment, the air gap between the first and second lenses is 1.5-2.0 mm; the air gap between the second and third lenses is 0.0-0.5 mm; the air gap between the third and fourth lenses is 0.0-0.5 mm; the air gap between the fourth lens and the aperture is 0.0--0.5 mm; the air gap between the aperture and the fifth lens is 0.0-0.5 mm; and the air gap between the sixth and seventh lenses is 0.0-0.5 mm. While meeting imaging requirements, reducing the distance between each lens element is beneficial to the overall optical length of the lens.

[0035] In this embodiment, the focal length of the optical system is The focal lengths of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens are 、 、 、 、 、 、 ,in 、 、 、 、 、 、 and Meet the following ratio: -3.0< / <-2.0, -3.0< / <-2.0, 4.0< / <5.0, 1.0< / <2.0, -1.0< / <0.0, 1.0< / <2.0,62.0< / <63.0.

[0036] In this embodiment, the first lens satisfies the relationship: 2.0≤ ≤2.5, ≤50.0; the second lens satisfies the relationship: 1.5≤ ≤1.8, ≥50.0; the third lens satisfies the relationship: 1.5≤ ≤2.0, ≤50.0; the fourth lens satisfies the relationship: 2.0≤ ≤2.5, ≤50.0; the fifth lens satisfies the relationship: 1.5≤ ≤2.0, ≤50.0; the sixth lens satisfies the relationship: 1.5≤ ≤1.8, ≥50.0; the seventh lens satisfies the relationship: 1.5≤ ≤1.8, ≥50.0; among them is the refractive index, is the Abbe constant.

[0037] In this embodiment, the total optical length TTL of the optical system and the focal length f of the optical system satisfy the following relationship: TTL / f≤8.

[0038] In this embodiment, the image height H of the optical system and the focal length f of the optical system satisfy: H / f≥1.0.

[0039] In this embodiment, the technical indicators achieved by the optical system are as follows:

[0040] (1) Focal length: 1.0 ≤ EFFL ≤ 2.0 mm;

[0041] (2) Aperture F ≤ 2.4;

[0042] (3) Field of view: 2w ≥ 180°;

[0043] (4) Working band: visible light band and 850nm band.

[0044] In this embodiment, to achieve the above design parameters, the specific design adopted by the optical system is shown in the following table:

[0045] .

[0046] In this embodiment, the aspheric curve equations of the second lens, the third lens, the fifth lens, the sixth lens, and the seventh lens are expressed as follows:

[0047]

[0048] Where Z is the height of the aspheric surface from the vertex of the aspheric surface at a height of h along the optical axis; c is the paraxial curvature of the aspheric surface; k is the conic constant; All are high-order coefficients.

[0049] In this embodiment, the aspheric coefficients of the aspheric lenses of the optical system are as follows:

[0050] .

[0051] In this embodiment, the optical system satisfies the requirements of small size and low cost while meeting the requirements of lens imaging performance by reasonably allocating the material, optical focal length, surface shape, center thickness of each lens, and axial distance between lenses.

[0052] In the imaging method of the above-mentioned small-volume and low-cost automotive OMS lens, light enters the first lens, the second lens, the third lens, the fourth lens, the aperture, the fifth lens, the sixth lens, the seventh lens, and the first equivalent glass plate and the second equivalent glass plate arranged behind the seventh lens from left to right, and then forms an image on the imaging surface.

[0053] The above description is only a preferred embodiment of the present invention. For ordinary technicians in this field, according to the teachings of the present invention, designing different forms of small-volume and low-cost vehicle-mounted OMS lenses does not require creative labor. All equivalent changes, modifications, substitutions and variations made within the scope of the patent application of the present invention without departing from the principles and spirit of the present invention should fall within the scope of the present invention.

Claims

1. A small-volume, low-cost vehicle-mounted OMS lens, characterized in that: The optical system of the lens consists of a first lens, a second lens, a third lens, a fourth lens, an aperture stop, a fifth lens, a sixth lens, and a seventh lens arranged in sequence from left to right along the light incident optical path; without considering the inflection caused by the aspherical coefficient, the first lens is a meniscus concave negative lens, the second lens is a meniscus concave negative lens, the third lens is a meniscus convex positive lens, the fourth lens is a biconvex positive lens, the fifth lens is a biconcave negative lens, the sixth lens is a biconvex positive lens, and the seventh lens is a meniscus convex positive lens. Among them, the fifth lens and the sixth lens form a cemented lens group, and the second lens, the third lens, the fifth lens, the sixth lens, and the seventh lens are aspherical lenses; 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, the sixth lens, and the seventh lens are f1, f2, f3, f4, f5, f6, and f7 respectively. Among them, f1, f2, f3, f4, f5, f6, and f7 satisfy the following ratios with f: -3.0 < f1 / f < -2.0, -3.0 < f2 / f < -2.0, 4.0 < f3 / f < 5.0, 1.0 < f4 / f < 2.0, -1.0 < f5 / f < 0.0, 1.0 < f6 / f < 2.0, 62.0 < f7 / f < 63.0; the total optical length TTL of the optical system and the focal length f of the optical system satisfy: TTL / f ≤ 8; the F number of the optical system ≤ 2.

4.

2. The small-volume, low-cost vehicle-mounted OMS lens according to claim 1, characterized in that: The object side surface of the first lens is convex, and the image side surface is concave; the object side surface of the second lens is convex, and the image side surface is concave; the object side surface of the third lens is convex, and the image side surface is concave; the object side surface of the fourth lens is convex, and the image side surface is convex; the object side surface of the fifth lens is concave, and the image side surface is concave; the object side surface of the sixth lens is convex, and the image side surface is convex; the object side surface of the seventh lens is convex, and the image side surface is concave.

3. A small-volume, low-cost vehicle-mounted OMS lens according to claim 1 or 2, characterized in that: The first lens and the fourth lens are both glass spherical lenses, and the second lens, the third lens, the fifth lens, the sixth lens, and the seventh lens are plastic aspherical lenses.

4. A small-volume, low-cost vehicle-mounted OMS lens according to claim 1 or 2, characterized in that: The air gap between the first lens and the second lens is: 1.5 - 2.0 mm; the air gap between the second lens and the third lens is: 0.0 - 0.5 mm; the air gap between the third lens and the fourth lens is: 0.0 - 0.5 mm; the air gap between the fourth lens and the aperture stop is: 0.0 - -0.5 mm; the air gap between the aperture stop and the fifth lens is: 0.0 - 0.5 mm; the air gap between the sixth lens and the seventh lens is: 0.0 - 0.5 mm.

5. The small-volume, low-cost vehicle-mounted OMS lens according to claim 1 or 2, characterized in that: The first lens satisfies the relationship: 2.0≤N d ≤2.5, V d ≤50.0; the second lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≥50.0; the third lens satisfies the relationship: 1.5≤N d ≤2.0, V d ≤50.0; the fourth lens satisfies the relationship: 2.0≤N d ≤2.5, V d ≤50.0; the fifth lens satisfies the relationship: 1.5≤N d ≤2.0, V d ≤50.0; the sixth lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≥50.0; the seventh lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≥50.0; where N d is the refractive index, V d is the Abbe constant.

6. The small-volume, low-cost vehicle-mounted OMS lens according to claim 1, characterized in that: The expression of the aspherical curve equation of the aspherical lens is: Where, z is the sagitta height from the vertex of the aspherical surface when the aspherical surface is at a position with a height of h along the optical axis direction; c is the paraxial curvature of the aspherical surface; r = 1 / c; k is the conic constant; α1, α2, α3, α4, α5, α6, α7, and α8 are all high-order term coefficients.

7. The small-volume, low-cost vehicle-mounted OMS lens according to claim 1 or 2, characterized in that: The image height H of the optical system and the focal length f of the optical system satisfy: H / f ≥ 1.

0.

8. An imaging method for a small-volume, low-cost vehicle-mounted OMS lens, comprising the small-volume, low-cost vehicle-mounted OMS lens according to claim 1, 2, or 6, characterized in that: Light enters the first lens, second lens, third lens, fourth lens, aperture, fifth lens, sixth lens, seventh lens, and the first equivalent glass plate and second equivalent glass plate arranged behind the seventh lens in sequence from left to right, and then forms an image on the imaging surface.

Images