Laser transceiver optical system and imaging method thereof

Abstract

The present invention relates to a laser transceiver optical system and an imaging method thereof, which is composed of a first lens, a second lens, a third lens, a fourth lens, an aperture, a fifth lens, and a sixth lens arranged in sequence from left to right along the incident direction of light; the first lens is a meniscus negative lens, the second lens is a meniscus negative lens, the third lens is a meniscus negative lens, the fourth lens is a biconvex positive lens, the fifth lens is a biconvex positive lens, and the sixth lens is a biconvex positive lens. The laser transceiver optical system has reasonable material matching and has low temperature drift characteristics within the temperature range of ‑40 to 120°C. The surface design is reasonable, the light incident angle is low, the tolerance sensitivity is low, and the theoretical yield is excellent. The aperture is extremely large, the imaging surface illumination is higher, and the peripheral illumination ratio is>80%, and the image surface illumination distribution is more uniform. The optical size is lower, and the total length is <3cm.

Description

Technical Field

[0001] The invention relates to a laser transceiver optical system and an imaging method thereof. Background Art

[0002] Compared with imaging lenses and millimeter-wave radars, LiDAR has higher resolution and better stability, and is currently recognized as a more reliable optical solution for three-dimensional data. LiDAR's advantages such as long detection distance and strong anti-interference ability have also made it popular with a number of car brands. Summary of the invention

[0003] The object of the present invention is to provide a laser transceiver optical system and an imaging method thereof, wherein the illumination distribution on the image plane of the laser transceiver optical system is more uniform.

[0004] The technical solution of the present invention is: a laser transceiver optical system, which is composed of a first lens, a second lens, a third lens, a fourth lens, an aperture, a fifth lens, and a sixth lens arranged in sequence from left to right along the incident direction of light; the first lens is a meniscus negative lens, the second lens is a meniscus negative lens, the third lens is a meniscus negative transparent lens, the fourth lens is a biconvex positive lens, the fifth lens is a biconvex positive lens, and the sixth lens is a biconvex positive lens.

[0005] Furthermore, a filter and a protective glass are arranged in sequence from left to right between the sixth lens and the imaging plane.

[0006] 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, and the sixth lens are respectively, Meet the following ratio: -17.0< <-14.1, -15.2< <-12.5, -22.1< <-18.4, 12.5< <15.5,7.7< <10.0, 10.2< <14.5.

[0007] Furthermore, the first lens satisfies the relationship: ≥1.5, ≤50.0; the second lens satisfies the relationship: ≥1.5, ≤50.0; the third lens satisfies the relationship: ≥1.5, ≥50.0; the fourth lens satisfies the relationship: ≥1.5, ≤50.0; the fifth lens satisfies the relationship: ≥1.5, ≤50.0; the sixth lens satisfies the relationship: ≥1.5, ≤50.0; where is the refractive index, is the Abbe constant.

[0008] Furthermore, the sixth lens is an aspherical lens.

[0009] Furthermore, the total optical length TTL of the optical system and the focal length f of the optical system satisfy: TTL / f≤10.0.

[0010] Furthermore, the F number of the optical system is ≤1.15.

[0011] Furthermore, the half image height ImaH of the optical system and the focal length f of the optical system satisfy: ImaH / f≥1.41.

[0012] An imaging method for a laser transceiver optical system is performed according to the following steps: light passes through a first lens, a second lens, a third lens, an aperture, a fourth lens, a fifth lens, a sixth lens, a filter and a protective glass from left to right to form an image on an imaging surface.

[0013] Compared with the prior art, the present invention has the following advantages:

[0014] The laser transceiver optical system has reasonable material matching and structural compensation, and has low temperature drift characteristics in the temperature range of -40 to 120°C. The surface design is reasonable, the light incident angle is low, the tolerance sensitivity is low, and the theoretical yield is excellent. The aperture is extremely large, the imaging surface illumination is higher, and the peripheral illumination ratio is >80%, and the image surface illumination distribution is more uniform. The optical size is lower, and the total length is <3cm. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a schematic diagram of the optical structure of the present invention;

[0016] Figure 2 It is the working band MTF diagram of the present invention;

[0017] Figure 3 is the axial aberration diagram of the working band of the present invention;

[0018] Figure 4 It is a field curvature distortion diagram of the working band of the present invention;

[0019] Figure 5 It is a peripheral illumination ratio diagram of the working band of the present invention;

[0020] In the figure: L1-first lens; L2-second lens; L3-third lens; L4-fourth lens; L5-fifth lens; L6-sixth lens; L7-filter; L8-protective glass; STO-aperture; IMA-imaging surface. DETAILED DESCRIPTION

[0021] In order to make the above features and advantages of the present invention more understandable, embodiments are given below with reference to the accompanying drawings for detailed description, but the present invention is not limited thereto.

[0022] refer to Figures 1 to 4

[0023] A laser transceiver optical system, comprising a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, an aperture STO, a fifth lens L5, and a sixth lens L6, which are arranged in sequence from left to right along the incident direction of light; the first lens is a meniscus negative lens, the second lens is a meniscus negative lens, the third lens is a meniscus negative transparent lens, the fourth lens is a biconvex positive lens, the fifth lens is a biconvex positive lens, and the sixth lens is a biconvex positive lens.

[0024] In this embodiment, a filter L7 and a protective glass L8 are sequentially arranged from left to right between the sixth lens and the imaging surface.

[0025] 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, and the sixth lens are respectively, Meet the following ratio: -17.0< <-14.1, -15.2< <-12.5, -22.1< <-18.4, 12.5< <15.5,7.7< <10.0, 10.2< <14.5.

[0026] In this embodiment, the first lens satisfies the relationship: ≥1.5, ≤50.0; the second lens satisfies the relationship: ≥1.5, ≤50.0; the third lens satisfies the relationship: ≥1.5, ≥50.0; the fourth lens satisfies the relationship: ≥1.5, ≤50.0; the fifth lens satisfies the relationship: ≥1.5, ≤50.0; the sixth lens satisfies the relationship: ≥1.5, ≤50.0; where is the refractive index, is the Abbe constant.

[0027] In this embodiment, the total optical length TTL of the optical system and the focal length f of the optical system satisfy: TTL / f≤10.0.

[0028] In this embodiment, the F number of the optical system is ≤1.15.

[0029] In this embodiment, the half image height ImaH of the optical system and the focal length f of the optical system satisfy: ImaH / f≥1.41.

[0030] In this embodiment, the sixth lens is an aspheric lens. The aspheric curve equation is:

[0031]

[0032] Wherein, Z is the height of the aspheric surface from the vertex of the aspheric surface when the aspheric surface is at a height of h along the optical axis; c is the paraxial curvature of the aspheric surface; k is the cone constant; , , , , , , , All are high-order coefficients.

[0033] In this embodiment, the aspheric coefficients of the aspheric lenses of the optical system are as follows:

[0034] .

[0035] In this embodiment, the design parameters for the optical system to achieve the following technical indicators are:

[0036] (1) Focal length: 2.8mm≤EFFL≤3.9mm; (2) Aperture F≤1.15; (3) Working band: near infrared. The specific design of the optical system is shown in the table below:

[0037] .

[0038] The imaging method of the above-mentioned laser transceiver optical system is carried out according to the following steps: the light passes through the first lens, the second lens, the third lens, the aperture, the fourth lens, the fifth lens, the sixth lens, the filter and the protective glass from left to right to form an image on the imaging surface.

[0039] 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 laser transceiver optical systems does not require creative labor. Without departing from the principles and spirit of the present invention, all equal changes, modifications, substitutions and variations made within the scope of the patent application of the present invention should fall within the scope of the present invention.

Claims

1. A laser transceiver optical system, characterized in that: It is composed of a first lens, a second lens, a third lens, a fourth lens, an aperture, a fifth lens, and a sixth lens which are arranged in sequence from left to right along the incident direction of light; the first lens is a meniscus negative lens, the second lens is a meniscus negative lens, the third lens is a meniscus negative lens, the fourth lens is a biconvex positive lens, the fifth lens is a biconvex positive lens, the sixth lens is a biconvex positive lens, and the sixth lens is an aspherical lens; the first lens satisfies the relationship: ≥1.5, ≤50.0; the second lens satisfies the relationship: ≥1.5, ≤50.0; the third lens satisfies the relationship: ≥1.5, ≥50.0; the fourth lens satisfies the relationship: ≥1.5, ≤50.0; the fifth lens satisfies the relationship: ≥1.5, ≤50.0; the sixth lens satisfies the relationship: ≥1.5, ≤50.0; where is the refractive index, is the Abbe constant; the F number of the optical system is ≤1.15; the half image height ImaH of the optical system and the focal length f of the optical system satisfy: ImaH / f≥1.

41.

2. A laser transceiver optical system according to claim 1, characterized in that: A filter and a protective glass are arranged in sequence from left to right between the sixth lens and the imaging surface.

3. An imaging method applied to a laser transceiver optical system according to claim 2, characterized in that: Proceed in the following steps: light rays pass through the first lens, the second lens, the third lens, the aperture, the fourth lens, the fifth lens, the sixth lens, the filter and the protective glass from left to right in sequence and then form an image on the imaging surface.

Images