Collimating cylindrical lens

Abstract

The collimating cylindrical lens sequentially comprises a first lens with positive focal power and a second lens with positive focal power from an object side to an image side along an optical axis, and the first lens and the second lens are cylindrical lenses; wherein the axial distance from the object side surface of the first lens to the image side surface of the second lens is TD, the sum of the medium thickness of the first lens and the medium thickness of the second lens is sigma CT, and the collimating cylindrical lens meets the condition that TD / sigma CT is larger than 1.5 and smaller than 2.0. According to the invention, a two-dimensional light source scanning at a certain angle on an image plane can be well collimated into parallel light, and the parallel light is emitted on an object plane, so that the problem that a high-performance collimation cylindrical lens capable of being matched with a solid-state scanning laser radar is urgently needed at present is solved; the lens adopts an aspheric surface in the curvature direction to realize correction of various aberrations of light rays and realize a light ray collimation effect; and meanwhile, by reasonably distributing the focal power and the surface type of each lens, the collimation capability of the collimation cylindrical lens is effectively improved, and the high-reliability lens is obtained.

Description

Technical Field

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

[0002] LiDAR technology uses lasers to calculate the distance to objects. Its core technologies include single-point ranging and two-dimensional scanning. Two-dimensional scanning technology is categorized into mechanical scanning, semi-solid scanning (one dimension without moving parts), and solid-state scanning, depending on whether the scanning principle involves moving parts. Solid-state scanning utilizes a two-dimensional light source (including linear and surface sources) and uses a chip to emit light. Its advantages include simple structure, small size, easy integration, low cost, and high reliability. These advantages make solid-state LiDAR a key area of ​​future LiDAR technology development, especially with broad application prospects in autonomous driving and intelligent transportation systems.

[0003] Currently, there is a severe shortage of collimating cylindrical lenses that can match solid-state scanning lidars on the market, especially collimating cylindrical lenses that can match the two-dimensional light source in solid-state scanning lidars. 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 described above, the purpose of this 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 lidar in the current market.

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

[0006] The axial distance from the object side surface of the first lens to the image side surface 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 this 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 out of 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 collimation effect.

[0011] In one embodiment of the present application, a stop is provided 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 a reduction in the yield of the collimating cylindrical lens due to the edge of the first lens being too thin during production, 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 a reduction in the yield of the collimating cylindrical lens due to the second lens edge being too thin during production, 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 on-axis 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-mentioned setting 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 is set above 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 solutions may have the following advantages or beneficial effects:

[0023] The collimating cylindrical lens provided in the embodiment of the present invention, through the arrangement of the first lens and the second lens, converts the light emitted by the two-dimensional light source on the image plane into parallel light after passing through the collimating lens, thus solving the current market problem of the urgent need for high-performance collimating cylindrical lenses that can match solid-state scanning laser radars. Furthermore, both the first lens and the second lens adopt aspherical surfaces in the direction of curvature to correct various aberrations of the light, thereby collimating the light emitted by the two-dimensional light source into parallel light, thereby achieving a better light collimation effect. At the same time, by rationally allocating the optical power and surface shape of each lens, the collimating ability of the collimating cylindrical lens is effectively improved, resulting in a highly reliable collimating cylindrical lens.

[0024] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present invention. The purposes 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 structural diagram of the YZ plane of the collimating cylindrical lens according to an embodiment of the present application.

[0027] Figure 2 Shown is an isometric structural 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 The diagram shows the energy circled along the Y direction on the image plane of the collimating cylindrical lens according to an embodiment of the present application.

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

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

[0032] Figure 7 It is a schematic diagram showing the structure of the XZ plane when the light of the collimating cylindrical lens according to an 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 according to an embodiment of the present application is tilted 10 degrees along the X direction. DETAILED DESCRIPTION

[0034] The following describes the embodiments of the present invention in detail with reference to the accompanying drawings and examples, so that the present invention can fully understand how to apply technical means to solve technical problems and achieve technical effects, and thus implement the invention accordingly. It should be noted that, as long as no conflict exists, the various embodiments of the present invention and the various features of the embodiments can be combined with each other, and the resulting technical solutions are all within the scope of protection 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. Therefore, the illustrations only show components related to the present application and are not drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component can be changed at will, and the component layout type 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 various other line scanning light source generating devices that have good and excellent performance requirements for collimating cylindrical lenses, and no fixed restrictions are imposed on it 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 comprising a first lens and a second lens, sequentially along the optical axis from the object side to the image side, wherein both the first lens and the second lens have positive optical power and are configured as cylindrical lenses. A cylindrical lens is a lens that has curvature in one direction and is flat in a direction perpendicular to the curvature. To ensure that the collimating cylindrical lens formed by the first and second lenses has a collimating function, this embodiment requires that the collimating cylindrical lens have optical power from the object side to the image side, while having no optical power in a direction perpendicular to the optical power direction.

[0040] The collimating cylindrical lens in this embodiment also meets the requirement of 1.5 < TD / ∑CT < 2.0, where TD is the on-axis 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 thicknesses of the first and second lenses. This setting allows the collimating cylindrical lens in this embodiment to be rationally structured and easier to assemble by properly distributing lens thickness within a given lens length.

[0041] In this embodiment, the collimating cylindrical lens can be configured such that the object-side surface of the first lens is convex and the image-side surface of the first lens is concave, i.e., the first lens can be configured as a convex-concave cylindrical lens. Furthermore, the object-side surface of the second lens can be configured such that the image-side surface of the second lens is convex, i.e., the second lens can be configured as a convex-convex cylindrical lens.

[0042] In one embodiment, both the first and second lenses are configured as plastic lenses. This configuration ensures the collimating effect of the collimating cylindrical lens while minimizing the manufacturing cost, overall length, and weight of the collimating cylindrical lens. Furthermore, the first and second lenses are configured as even-order aspheric surfaces in the direction of curvature, wherein the even-order aspheric surfaces of the first and second lenses conform to the following formula:

[0043]

[0044] in, is the axial sag of the even aspheric surface, r is the radial distance of the even aspheric surface, that is, the distance from the optical axis to a point on the surface; c is the curvature of the even aspheric surface, and k is the conic coefficient, which is used to describe the shape of the even aspheric surface; 、 、 、 is the coefficient of the even-order aspheric surface, which is used to describe the specific shape of the aspheric surface. In one embodiment, a stop is further provided inside the collimating cylindrical lens, and the stop is specifically provided 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 operating band of the collimating cylindrical lens is 1528nm-1568nm.

[0046] In one embodiment, the first lens element in the collimating cylindrical lens must also satisfy ET1 / CT1 > 0.2, where ET1 is the edge thickness of the first lens element and CT1 is the center thickness of the first lens element along the optical axis. This configuration effectively prevents the first lens element from being too thin at the edge during manufacturing, which could reduce the yield of the collimating cylindrical lens, while also effectively improving the manufacturability of the first lens element.

[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 axial 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 8 mm < f < 12 mm, 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 solutions claimed in 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 embodiments, the collimating cylindrical lens is not limited to including two lenses, and 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, in this embodiment, the collimating cylindrical lens 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 Z-axis is set as the Y-axis. Figure 1 、 Figure 2 、 Figure 3 [[ID=S2]] / 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] During actual use, the two-dimensional light source of the solid-state scanning lidar at different heights on the image plane will cause the collimated parallel light to have different exit angles along the Y direction. The collimating cylindrical lens of this embodiment supports the exit angle of the collimated 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 Schematic diagrams of the lens seen in the XZ plane when a two-dimensional light source scans 0 degrees, 5 degrees, and 10 degrees along the X direction.

[0054] This embodiment of the collimating cylindrical lens ensures that all light rays from a two-dimensional light source are collimated into parallel rays when scanning along the X-direction, ensuring excellent collimation. Because this embodiment of the collimating cylindrical lens utilizes an inverse design, the energy enclosed by the image plane along the Y-direction can be used as a primary indicator for evaluating lens performance.

[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 of a 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] The first lens L1 and the second lens L2 are both cylindrical lenses. The first lens L1 has positive refractive power, with its object-side surface S1 being convex and its image-side surface S2 being concave. The second lens L2 has positive refractive power, with its object-side surface S3 being convex and its image-side surface S4 being 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 shows the basic parameters of a collimating cylindrical lens of a specific example, wherein the units of the curvature radius, thickness, and effective focal length are all in millimeters (mm).

[0059] Table 1

[0060]

[0061] Table 2 shows the high-order coefficients a4, a6, a8 and a2 of the object-side surface S1 and image-side surface S2 of the first lens L1, and the object-side surface S3 and image-side surface S4 of the second lens L2 that can be used in the above specific example. 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 center thicknesses 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 on-axis 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 diagram along the Y direction. Figure 5 It can represent the structural schematic diagram of the XZ plane when the collimating cylindrical lens light in the above specific example is tilted 5 degrees along the X direction. Figure 6 for Figure 5 The image plane is circled along the Y direction when the light of the collimating cylindrical lens is tilted 5 degrees along the X direction. Figure 7 It can represent the structural schematic diagram of the XZ plane when the collimating cylindrical lens light in the above specific example is tilted 10 degrees along the X direction. Figure 8 for Figure 7 The diagram shows the energy of the image plane along the Y direction when the light of the collimating cylindrical lens is tilted 10 degrees along the X direction.

[0073] refer to Figure 3-Figure 8 As 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 an embodiment of the present invention, through the arrangement of a first lens and a second lens, converts light emitted from a two-dimensional light source on the image plane into parallel light after passing through the collimating lens, thereby solving the current market problem of the urgent need for a high-performance collimating cylindrical lens that can match two-dimensional light sources. Furthermore, both the first lens and the second lens utilize aspheric surfaces in the direction of curvature to correct various aberrations of the light, thereby collimating the light emitted from the two-dimensional light source into parallel light, thereby achieving a better light collimation effect. Simultaneously, by rationally allocating the optical power and surface shape of each lens, the collimating capability of the collimating cylindrical lens is effectively improved, resulting in a highly reliable collimating cylindrical lens.

[0075] Although the embodiments disclosed herein are as described above, the contents described herein are merely embodiments for facilitating understanding of the present invention and are not intended to limit the present invention. Any person skilled in the art may make any modifications and variations in the form and details of the embodiments without departing from the spirit and scope of the present invention. However, the scope of protection of the present invention shall remain subject to the scope defined by the appended 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 thicknesses of the first lens and the second lens is ΣCT, and the collimating cylindrical lens satisfies: 1.5<TD / ΣCT<2.

0.

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 numerical aperture of the collimating cylindrical lens is NA, and the collimating cylindrical lens satisfies: 0.3 <NA<0.6。 9. 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。 10. The collimating cylindrical lens according to claim 1, characterized in that: The working band of the collimating cylindrical lens is 1528nm-1568nm.

Images