Collimating cylindrical lens

Abstract

The present invention discloses a collimating cylindrical lens, which includes a first lens with positive optical power and a second lens with positive optical power in sequence from the object side to the image side along the optical axis, and the first lens and the second lens are both cylindrical lenses; wherein the on-axis distance from the object side of the first lens to the image side of the second lens is TD, the sum of the middle thickness of the first lens and the second lens is ∑CT, and the collimating cylindrical lens satisfies: 1.5<TD / ∑CT<2.0. The present invention enables a two-dimensional light source scanned along a certain angle on the image plane to be well collimated into parallel light and emitted on the object plane, solving the problem of the urgent need for a high-performance collimating cylindrical lens that can match a solid-state scanning laser radar; the lens adopts a non-spherical surface in the curvature direction to realize the correction of various aberrations of light and achieve the light collimation effect; at the same time, by reasonably allocating the optical power and surface shape of each lens, the collimation ability of the collimating cylindrical lens is effectively improved, and a high-reliability lens is obtained.

Description

Technical Field

[0001] The invention relates to the technical field of optical imaging, and in particular to a collimating cylindrical lens. Background Art

[0002] LiDAR technology is a technology that uses lasers to calculate the distance of objects. The core technologies include single-point ranging and two-dimensional scanning. Among them, two-dimensional scanning technology is divided into mechanical scanning, semi-solid scanning (one dimension has no moving parts), and solid-state scanning according to whether there are moving parts on its scanning principle. Solid-state scanning uses chip light output, and the light source used is a two-dimensional light source (including line light source and surface light source). Its advantages are simple structure, small size, easy integration, low cost and high reliability. These advantages make solid-state LiDAR an important direction for the development of LiDAR technology in the future, especially in autonomous driving and intelligent transportation systems, with broad application prospects.

[0003] At present, there is a severe shortage of collimating cylindrical lenses that can match solid-state scanning laser radars in the market, especially collimating cylindrical lenses that match the two-dimensional light source in solid-state scanning laser radars. Therefore, there is an urgent need for a collimating cylindrical lens with good reliability and excellent performance. Summary of the invention

[0004] In view of the shortcomings of the prior art mentioned above, the purpose of the present application is to provide a collimating cylindrical lens to solve the problem that there is a severe lack of collimating cylindrical lenses with good reliability and excellent performance that can match solid-state scanning laser radars in the existing market.

[0005] In a first aspect, the present application provides a collimating cylindrical lens, which includes a first lens with positive optical power and a second lens with positive optical power in sequence from the object side to the image side along the optical axis, wherein the first lens and the second lens are both cylindrical lenses;

[0006] The axial distance from the object side of the first lens to the image side of the second lens is TD, the sum of the center thicknesses of the first lens and the second lens is ΣCT, and the collimating cylindrical lens satisfies: 1.5<TD / ΣCT<2.0.

[0007] In the present application, the above-mentioned setting can ensure that the two-dimensional light source scanned along a certain angle on the image plane can be well collimated into parallel light and emitted on the object plane; at the same time, the design of 1.5<TD / ∑CT<2.0 reasonably distributes the lens thickness under a certain lens length, making the collimating cylindrical lens structure reasonable and easier to assemble.

[0008] In one embodiment of the present application, the object-side surface of the first lens is convex, and the image-side surface of the first lens is concave; the object-side surface of the second lens is convex, and the image-side surface of the second lens is convex.

[0009] In one embodiment of the present application, both the first lens and the second lens are plastic lenses.

[0010] In the present application, the above-mentioned setting can ensure that the collimating cylindrical lens can reduce the cost, reduce the total length of the lens, and reduce the weight of the lens as much as possible while ensuring the collimating effect.

[0011] In one embodiment of the present application, a stop is disposed on the object-side surface of the first lens.

[0012] In one embodiment of the present application, the edge thickness of the first lens is ET1, the center thickness of the first lens on the optical axis is CT1, and the first lens satisfies: ET1 / CT1>0.2.

[0013] In the present application, the above arrangement can avoid the reduction in the yield of the collimating cylindrical lens due to the excessive thinness of the edge of the first lens during manufacturing, thereby effectively improving the manufacturability of the first lens.

[0014] In one embodiment of the present application, the edge thickness of the second lens is ET2, the center thickness of the second lens on the optical axis is CT2, and the second lens satisfies: ET2 / CT2>0.2.

[0015] In the present application, the above arrangement can avoid the reduction in the yield of the collimating cylindrical lens due to the second lens edge being too thin during manufacturing, thereby effectively improving the manufacturability of the second lens.

[0016] In one embodiment of the present application, the effective focal length of the collimating cylindrical lens is f, the axial distance from the object side of the first lens to the image side of the second lens is TD, and the collimating cylindrical lens satisfies: 1 <TD / f<3。

[0017] In the present application, the above arrangement can not only prevent the length of the collimating cylindrical lens from being too long, but also obtain a larger focal length while minimizing the aperture of the collimating cylindrical lens, thereby making the collimating cylindrical lens perform better.

[0018] In one embodiment of the present application, the numerical aperture of the collimating cylindrical lens is NA, and the collimating cylindrical lens satisfies: 0.3 <NA<0.6。

[0019] In the present application, the large numerical aperture in the above setting is used to ensure that the collimating cylindrical lens can collimate a two-dimensional light source with a large numerical aperture.

[0020] In one embodiment of the present application, the effective focal length of the collimating cylindrical lens is f, and the collimating cylindrical lens satisfies: 8mm <f<12mm。

[0021] In one embodiment of the present application, the operating wavelength band of the collimating cylindrical lens is 1528nm-1568nm.

[0022] Compared with the prior art, one or more embodiments of the above scheme may have the following advantages or beneficial effects:

[0023] By using the collimating cylindrical lens provided in the embodiment of the present invention, the light emitted by the two-dimensional light source on the image plane is transformed into parallel light after passing through the collimating lens by setting the first lens and the second lens, which solves the problem that the market is in urgent need of a high-performance collimating cylindrical lens that can match the solid-state scanning laser radar. Furthermore, both the first lens and the second lens use aspherical surfaces in the curvature direction to correct various aberrations of the light, thereby collimating the light emitted by the two-dimensional light source into parallel light, and better achieving the light collimation effect; at the same time, by reasonably allocating the optical focal length and surface shape of each lens, the collimating ability of the collimating cylindrical lens is effectively improved, and a highly reliable collimating cylindrical lens is obtained.

[0024] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0026] Figure 1 Shown is a schematic diagram of the structure of the YZ plane of the collimating cylindrical lens described in an embodiment of the present application.

[0027] Figure 2 Shown is an isometric structural schematic diagram of the collimating cylindrical lens described in an embodiment of the present application.

[0028] Figure 3 Shown is a schematic structural diagram of the XZ plane of the collimating cylindrical lens described in an embodiment of the present application.

[0029] Figure 4 It is a schematic diagram showing the energy circled along the Y direction on the image plane of the collimating cylindrical lens described in an embodiment of the present application.

[0030] Figure 5 It is a schematic diagram of the structure of the XZ plane when the collimating cylindrical lens light of the embodiment of the present application is tilted 5 degrees along the X direction.

[0031] Figure 6 It is a schematic diagram showing the energy of the image plane along the Y direction when the light of the collimating cylindrical lens described in the embodiment of the present application is tilted 5 degrees along the X direction.

[0032] Figure 7 It is a schematic diagram of the structure of the XZ plane when the light of the collimating cylindrical lens described in the embodiment of the present application is tilted 10 degrees along the X direction.

[0033] Figure 8 It is a schematic diagram showing the energy of the image plane along the Y direction when the light of the collimating cylindrical lens described in the embodiment of the present application is tilted 10 degrees along the X direction. DETAILED DESCRIPTION

[0034] The following will describe the implementation methods of the present invention in detail with reference to the accompanying drawings and embodiments, so that the implementation process of how the present invention applies technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly. It should be noted that as long as there is no conflict, the various embodiments of the present invention and the various features in the embodiments can be combined with each other, and the technical solutions formed are all within the protection scope of the present invention.

[0035] It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present application, and thus the drawings only show components related to the present application rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed at will, and the component layout may also be more complicated.

[0036] The purpose of the present invention is to provide a collimating cylindrical lens to solve the problem that there is a severe lack of collimating cylindrical lenses with good reliability and excellent performance that can match solid-state scanning laser radars in the existing market.

[0037] The collimating cylindrical lens of the present invention can be applied to existing solid-state scanning laser radars, and can also be applied to other types of line scanning light source generating devices that have good and excellent performance requirements for collimating cylindrical lenses, and no fixed restrictions are made here.

[0038] The principle and implementation of a collimating cylindrical lens of this embodiment will be described in detail below with reference to the accompanying drawings, so that those skilled in the art can understand the collimating cylindrical lens of this embodiment without creative work.

[0039] refer to Figure 1 As shown, this embodiment provides a collimating cylindrical lens, specifically including a first lens and a second lens in sequence from the object side to the image side along the optical axis, wherein both the first lens and the second lens have positive optical power, and both the first lens and the second lens are configured as cylindrical lenses. A cylindrical lens is a lens that has curvature in one direction and is a plane in a direction perpendicular to the curvature direction. In order to make the collimating cylindrical lens formed by the first lens and the second lens have a collimating function, this embodiment needs to set the collimating cylindrical lens to have optical power from the object side to the image side, and no optical power in a direction perpendicular to the optical power direction.

[0040] At the same time, the collimating cylindrical lens in this embodiment must also satisfy 1.5<TD / ∑CT<2.0, where TD is the axial distance from the object side of the first lens to the image side of the second lens, and ∑CT is the sum of the median thickness of the first lens and the second lens. The above setting allows the collimating cylindrical lens in this embodiment to reasonably distribute the lens thickness under a certain lens length, making the lens structure reasonable and easier to assemble.

[0041] In this embodiment, the collimating cylindrical lens can set the object side surface of the first lens to be convex, and the image side surface of the first lens to be concave, that is, the first lens can be set as a convex-concave cylindrical lens. At the same time, the object side surface of the second lens can be set as a convex surface, and the image side surface of the second lens can be set as a convex surface, that is, the second lens can be set as a convex-convex cylindrical lens.

[0042] In one embodiment, the first lens and the second lens in this embodiment can both be set as plastic lenses. This setting can reduce the production cost of the collimating cylindrical lens as much as possible, reduce the total length of the collimating cylindrical lens, and reduce the total weight of the collimating cylindrical lens while ensuring the collimating effect of the collimating cylindrical lens. At the same time, the first lens and the second lens are set to be even-order aspheric surfaces in the curvature direction, wherein the even-order aspheric surface shapes of the first lens and the second lens both meet the following formula:

[0043]

[0044] in, is the axial sag of the even-order aspheric surface, r is the radial distance of the even-order aspheric surface, that is, the distance from the optical axis to a point on the surface; c is the curvature of the even-order aspheric surface, and k is the cone coefficient, which is used to describe the shape of the even-order aspheric surface; , , , is the coefficient of the even-order aspheric surface, and is used to describe the specific shape of the aspheric surface. In one embodiment, a stop is further disposed inside the collimating cylindrical lens, and the stop is specifically disposed on the object-side surface of the first lens.

[0045] When the collimating cylindrical lens of this embodiment is actually used, the light emitted by the two-dimensional light source on the image plane is converted into parallel light after passing through the collimating cylindrical lens. The working band of the collimating cylindrical lens is 1528nm-1568nm.

[0046] In one embodiment, the first lens in the collimating cylindrical lens must also satisfy ET1 / CT1>0.2, where ET1 is the edge thickness of the first lens, and CT1 is the center thickness of the first lens on the optical axis. This setting can effectively prevent the edge of the first lens from being too thin during production, which may lead to a decrease in the yield of the collimating cylindrical lens, and also effectively improve the manufacturability of the first lens.

[0047] In one embodiment, the second lens in the collimating cylindrical lens further needs to satisfy ET2 / CT2>0.2, where ET2 is the edge thickness of the second lens and CT2 is the central thickness of the second lens on the optical axis. This setting can effectively prevent the edge of the second lens from being too thin during manufacturing, resulting in a reduction in the yield of the collimating cylindrical lens. At the same time, it also effectively improves the manufacturability of the second lens.

[0048] In one embodiment, the collimating cylindrical lens further needs to satisfy 1<TD / f<3, where f is the effective focal length of the collimating cylindrical lens and TD is the on-axis distance from the object side surface of the first lens to the image side surface of the second lens. This setting can avoid the collimating cylindrical lens from being too long, and while minimizing the aperture of the collimating cylindrical lens as much as possible, it can obtain a larger focal length, making the collimating cylindrical lens perform better.

[0049] In one embodiment, the collimating cylindrical lens further satisfies 0.3<NA<0.6, where NA is the numerical aperture of the collimating cylindrical lens. This setting can make the collimating cylindrical lens have a large numerical aperture, and this setting can ensure that the collimating cylindrical lens can collimate a two-dimensional light source with a large numerical aperture.

[0050] In one embodiment, the collimating cylindrical lens further satisfies 8mm<f<12mm, where f is the effective focal length of the collimating cylindrical lens.

[0051] Those skilled in the art should understand that without departing from the technical solution required to be protected by this application, the number of lenses constituting the collimating cylindrical lens can be changed to obtain the various results and advantages described in this specification. For example, although two lenses are described as an example in the embodiment, the collimating cylindrical lens is not limited to including two lenses. If necessary, the collimating cylindrical lens can also include other numbers of lenses.

[0052] To more clearly understand the collimating cylindrical lens of this embodiment, the collimating cylindrical lens of this embodiment is set as the Z-axis along the object side to the image side direction, the two-dimensional light source scanning direction is set as the X-axis, and the direction perpendicular to the X-axis and the Z-axis is set as the Y-axis. Figure 1 、 Figure 2 、 Figure 3 / Figure 5 / Figure 7 Structural schematic diagrams of the lens (taking a line light source as an example) are respectively given from different perspectives (i.e., coordinate planes).

[0053] In the actual use process, the two-dimensional light source of the solid-state scanning lidar at different heights on the image plane will cause the outgoing angle of the collimated parallel light along the Y direction to be different. The collimating cylindrical lens of this embodiment supports the outgoing angle of the parallel light along the Y direction to be ±15 degrees, and at the same time, the two-dimensional light source scans at an angle of ±10 degrees along the X direction. Figure 3 、 Figure 5 和 Figure 7 These are schematic diagrams of the lens seen in the XZ plane when the two-dimensional light source scans 0 degrees, 5 degrees and 10 degrees along the X direction.

[0054] The collimating cylindrical lens of this embodiment can ensure that all light rays can be collimated into parallel light rays when the two-dimensional light source scans along the X direction, and can ensure a good collimation effect. Since the collimating cylindrical lens of this embodiment adopts a reverse design, the schematic diagram of the energy enclosed by the image plane along the Y direction can be used as the main indicator for evaluating the performance of the lens.

[0055] On this basis, a specific design example of a collimating cylindrical lens is given below with reference to the above settings.

[0056] A specific example of a collimating cylindrical lens can also be found in the lens structure diagram Figure 1 and Figure 2 A specific example collimating cylindrical lens includes a first lens L1 and a second lens L2 in sequence from the object side to the image side along the optical axis.

[0057] Among them, the first lens L1 and the second lens L2 are both cylindrical lenses. The first lens L1 has positive optical power, its object side S1 is convex, and its image side S2 is concave; the second lens L2 has positive optical power, its object side S3 is convex, and its image side S4 is convex; S0 is the object surface, and S5 is the image surface. The first lens L1 and the second lens L2 are placed in parallel so that the collimating cylindrical lens has optical power from the object side to the image side.

[0058] Table 1 is a basic parameter table of a collimating cylindrical lens of a specific example, wherein the units of the radius of curvature, thickness, and effective focal length are all millimeters (mm).

[0059] Table 1

[0060]

[0061] Table 2 shows the high-order coefficients a of the object-side surface S1 and the image-side surface S2 of the first lens L1, and the object-side surface S3 and the image-side surface S4 of the second lens L2 in the above specific example. 4 、a 6 、a 8 and a 10 .

[0062] Table 2

[0063]

[0064] The main value parameters in the specific example are as follows: the effective focal length f of the collimating cylindrical lens is 9.3 mm, the total length of the collimating cylindrical lens is 17.62 mm, the total width of the collimating cylindrical lens is 24 mm, the half image height of the collimating cylindrical lens is 2.44 mm, and the numerical aperture NA of the collimating cylindrical lens is 0.47.

[0065] The collimating cylindrical lens in the specific example satisfies:

[0066] TD / ∑CT=1.827, where TD is the axial distance from the object side surface of the first lens to the image side surface of the second lens, and ∑CT is the sum of the median thickness of the first lens and the second lens.

[0067] ET1 / CT1=0.675, where ET1 is the edge thickness of the first lens, and CT1 is the center thickness of the first lens on the optical axis.

[0068] ET2 / CT2=0.28, where ET2 is the edge thickness of the second lens, and CT2 is the center thickness of the second lens on the optical axis.

[0069] TD / f=1.572, where f is the effective focal length of the collimating cylindrical lens, and TD is the axial distance from the object side of the first lens to the image side of the second lens.

[0070] NA=0.47, where NA is the numerical aperture of the collimating cylindrical lens.

[0071] f=9.3, where f is the effective focal length of the collimating cylindrical lens.

[0072] Figure 3 The schematic diagram of the structure of the XZ plane of the collimating cylindrical lens in the above specific example can be represented. Figure 4 for Figure 3 The image plane of the collimating cylindrical lens shown is circled in the energy schematic diagram along the Y direction. Figure 5 The schematic diagram of the structure of the XZ plane when the collimated cylindrical lens light in the above specific example is tilted 5 degrees along the X direction. Figure 6 for Figure 5 The energy diagram of the image plane along the Y direction when the light of the collimating cylindrical lens is tilted 5 degrees along the X direction is shown. Figure 7 The schematic diagram of the structure of the XZ plane when the collimated cylindrical lens light in the above specific example is tilted 10 degrees along the X direction. Figure 8 for Figure 7 The energy diagram of the image plane along the Y direction when the light of the collimating cylindrical lens is tilted 10 degrees along the X direction is shown.

[0073] refer to Figure 3-Figure 8As shown, the collimating cylindrical lens of the specific example can collimate the light into parallel light when the two-dimensional light source is scanned along the X direction, and can ensure a good collimation effect.

[0074] The collimating cylindrical lens provided in the embodiment of the present invention, by setting the first lens and the second lens, makes the light emitted by the two-dimensional light source on the image plane become parallel light after passing through the collimating lens, solving the problem that the market is in urgent need of a high-performance collimating cylindrical lens that can match the two-dimensional light source. Furthermore, both the first lens and the second lens use aspherical surfaces in the curvature direction to achieve the correction of various aberrations of the light, thereby achieving the collimation of the light emitted by the two-dimensional light source into parallel light, and better achieving the light collimation effect; at the same time, by reasonably allocating the focal length and surface shape of each lens, the collimation ability of the collimating cylindrical lens is effectively improved, and a highly reliable collimating cylindrical lens is obtained.

[0075] Although the embodiments disclosed in the present invention are as above, the contents described are only embodiments adopted for facilitating the understanding of the present invention and are not intended to limit the present invention. Any technician in the technical field to which the present invention belongs can make any modifications and changes in the form and details of the implementation without departing from the spirit and scope disclosed in the present invention, but the protection scope of the present invention shall still be subject to the scope defined in the attached claims.

Claims

1. A collimating cylindrical lens, characterized in that: The optical axis includes a first lens having positive optical power and a second lens having positive optical power in sequence from the object side to the image side, wherein both the first lens and the second lens are cylindrical lenses; The axial distance from the object side of the first lens to the image side of the second lens is TD, the sum of the center thickness of the first lens and the second lens is ∑CT, and the collimating cylindrical lens satisfies: 1.5<TD / ∑CT<2.0; the numerical aperture of the collimating cylindrical lens is NA, and the collimating cylindrical lens satisfies: 0.3 <NA<0.6。 2. The collimating cylindrical lens according to claim 1, characterized in that: The object side surface of the first lens is convex, and the image side surface of the first lens is concave; the object side surface of the second lens is convex, and the image side surface of the second lens is convex.

3. The collimating cylindrical lens according to claim 1, characterized in that: The first lens and the second lens are both plastic lenses.

4. The collimating cylindrical lens according to claim 1, characterized in that: The object side surface of the first lens is provided with an aperture stop.

5. The collimating cylindrical lens according to claim 1, characterized in that: The edge thickness of the first lens is ET1, the center thickness of the first lens on the optical axis is CT1, and the first lens satisfies: ET1 / CT1>0.

2.

6. The collimating cylindrical lens according to claim 1, characterized in that: The edge thickness of the second lens is ET2, the center thickness of the second lens on the optical axis is CT2, and the second lens satisfies: ET2 / CT2>0.

2.

7. The collimating cylindrical lens according to claim 1, characterized in that: The effective focal length of the collimating cylindrical lens is f, the axial distance from the object side of the first lens to the image side of the second lens is TD, and the collimating cylindrical lens satisfies: 1 <TD / f<3。 8. The collimating cylindrical lens according to claim 1, characterized in that: The effective focal length of the collimating cylindrical lens is f, and the collimating cylindrical lens satisfies: 8mm <f<12mm。 9. The collimating cylindrical lens according to claim 1, characterized in that: The working band of the collimating cylindrical lens is 1528nm-1568nm.

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