Optical system, optical module and method for mounting the same

Abstract

The application discloses an optical system, an optical module and a mounting method thereof. The optical system comprises a lens group and a microstructure array located on a transmission light path of the lens group. The microstructure array comprises a plurality of microstructures distributed along a first direction and a second direction, and the first direction and the second direction have an included angle. An optical parameter of the microstructure along the first direction satisfies a preset condition, so that a focal length of the optical system along the first direction is smaller than a focal length of the optical system along the second direction. The optical parameter comprises a focal length and / or a radius of curvature. The optical module comprises a photosensitive chip, a size of the photosensitive chip along a first direction is greater than a size of the photosensitive chip along a second direction, an optical system, and the photosensitive chip is located on an imaging surface of the optical system. The imaging surface is located on a side of the microstructure array of the optical system away from the lens group.

Description

Technical Field

[0001] This application relates to the field of optical component technology, and in particular to optical systems, optical modules and their mounting methods. Background Technology

[0002] Optical modules are essential components in machine vision systems and are widely used in many fields. For example, they are used in automotive applications such as reversing cameras, 360° panoramic views, autonomous driving assistance, and LiDAR detection.

[0003] An optical module typically includes an optical lens and a photosensitive chip. The photosensitive chip is located on the imaging surface of the optical lens. External light passing through the optical lens forms a light spot that illuminates the photosensitive chip, which then converts the received light spot into an electrical signal. In related technologies, optical lenses generally consist of multiple lenses spaced apart along the optical axis. These lenses are usually symmetrical about the optical axis center; for example, a circular lens can be used, resulting in a circular light spot after external light passes through the lens. However, some photosensitive chips are rectangular or elliptical. Along the length of the photosensitive chip, the circular light spot only illuminates a portion of the photosensitive area, leaving the remaining area untouched by light, thus wasting the photosensitive area. Summary of the Invention

[0004] The optical system, optical module, and installation method provided in this application can solve or partially solve the above-mentioned deficiencies or other deficiencies in the prior art.

[0005] An optical system according to a first aspect embodiment of this application includes:

[0006] Lens group; and

[0007] A microstructure array is located on the transmission light path of the lens group. The microstructure array includes multiple microstructures distributed along a first direction and a second direction, wherein the first direction and the second direction have an included angle.

[0008] Wherein, the optical parameters of the microstructure along the first direction satisfy a preset condition, such that the focal length of the optical system along the first direction is less than the focal length of the optical system along the second direction, and the optical parameters include focal length and / or radius of curvature.

[0009] According to one embodiment of this application, the optical parameters include focal length, and the preset conditions include the focal length Fy1 of the microstructure along the first direction and the focal length Fy2 of the lens group along the first direction satisfying: |Fy1 / Fy2|≥1.1.

[0010] According to one embodiment of this application, the optical parameters include focal length, and the preset conditions include the focal length Fy1 of the microstructure along the first direction, the focal length Fy2 of the lens group along the first direction, and the air gap d between the lens group and the microstructure array satisfying: 0.10≤Fy2 / (Fy1*SQRT(d))).

[0011] According to one embodiment of this application, the microstructure array further includes a substrate on which a plurality of the microstructures are arrayed on one side facing the lens group and / or the side away from the lens group.

[0012] According to one embodiment of this application, the microstructure has a convex surface that protrudes in a direction away from the substrate along the optical axis of the lens group; wherein the optical parameters include the radius of curvature, and the preset condition includes the radius of curvature R of the convex surface along the first direction and the focal length Fy0 of the optical system along the first direction satisfying: |R / Fy0|≥0.5.

[0013] According to one embodiment of this application, the focal length Fy0 of the optical system along the first direction and the focal length Fx0 of the optical system along the second direction satisfy: Fx0 / Fy0≥1.01.

[0014] According to one embodiment of this application, the maximum aperture D of the microstructure array, the image height H corresponding to the maximum field of view of the optical system, and the distance BFL between the center of the image side of the microstructure array and the center of the imaging surface of the optical system satisfy: D*BFL / H≥5.

[0015] According to one embodiment of this application, the focal length F of the optical system and the entrance pupil diameter ENPD of the optical system satisfy: F / ENPD≤2.

[0016] According to one embodiment of this application, the distance BFL between the center of the image side of the microstructure array and the center of the imaging surface of the optical system and the total optical length TTL of the optical system satisfy: BFL / TTL≥0.1.

[0017] According to one embodiment of this application, the total optical length (TTL) of the optical system, the maximum field of view (FOV) of the optical system, and the image height (H) corresponding to the maximum field of view of the optical system satisfy: TTL / H / FOV≤0.3.

[0018] According to one embodiment of this application, at least two of the plurality of microstructures have different thicknesses along the optical axis.

[0019] According to one embodiment of this application, the difference between the maximum thickness of the microstructure and the minimum thickness of the microstructure is no greater than 0.1 mm.

[0020] An optical module according to a second aspect embodiment of this application includes:

[0021] The photosensitive chip has a dimension along the first direction that is larger than its dimension along the second direction; and

[0022] In the optical system described in the first aspect of this application, the photosensitive chip is located on the imaging surface of the optical system, and the imaging surface is located on the side of the microstructure array of the optical system away from the lens group.

[0023] The method for mounting an optical module according to a third aspect embodiment of this application includes:

[0024] The microstructure array and lens group are sequentially installed into the lens barrel along the object side to the image side to form an optical system;

[0025] The photosensitive chip is fixed to the surface of the circuit board; and

[0026] The lens barrel is fixed to the circuit board and the lens barrel is placed on the photosensitive chip;

[0027] The microstructure array includes multiple microstructures distributed along a first direction and a second direction. The optical parameters of the microstructures along the first direction meet preset conditions so that the focal length of the optical system along the first direction is less than the focal length of the optical system along the second direction. The optical parameters include focal length and / or radius of curvature. The size of the photosensitive chip along the first direction is greater than its size along the second direction. The first direction and the second direction have an angle between them.

[0028] The optical system, optical module, and installation method provided in this application reduce the focal length of the entire optical system along the first direction by setting a microstructure array in the transmission optical path of the lens group and ensuring that the optical parameters of the microstructures in the microstructure array meet preset conditions along the first direction. This makes the focal length of the optical system along the first direction smaller than its focal length along the second direction. External light passes through the lens group and then strikes the microstructure array. The light passing through the microstructures first converges and then diverges, ultimately forming a light spot that is stretched and elongated along the first direction. In other words, the light spot formed on the imaging surface of the optical system is an elongated strip-shaped light spot extending along the first direction. Therefore, when the optical system of this application is applied to an optical module, it not only improves the utilization rate of the photosensitive area of ​​the photosensitive chip but also does not affect the energy of the light spot. Furthermore, the microstructure array is easy to manufacture, low in cost, and easy to mass-produce.

[0029] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of this application, nor is it intended to limit the scope of this application. Other features of this application will become readily apparent from the following description. Attached Figure Description

[0030] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings. The drawings are provided for a better understanding of the invention and are not intended to limit the scope of the application. In the drawings:

[0031] Figure 1 It is an image of the light spot formed on the imaging surface by an optical system in existing technology;

[0032] Figure 2 This is a schematic diagram of the optical system according to this application;

[0033] Figure 3 This is a schematic diagram of the microstructure array according to this application;

[0034] Figure 4 These are schematic diagrams of the optical modules according to Embodiments 1 and 2 of this application;

[0035] Figure 5 This is an image of the light spot formed on the imaging surface by the optical system according to Embodiment 1 of this application;

[0036] Figure 6 This is an image of the light spot formed on the imaging surface by the optical system according to Embodiment 2 of this application;

[0037] Figure 7 This is a schematic diagram of the optical module according to Embodiment 3 of this application;

[0038] Figure 8 This is an image of the light spot formed on the imaging surface by the optical system according to Embodiment 3 of this application;

[0039] Figure 9 This is a schematic diagram of the structure of the optical module according to Embodiment 4 of this application; and

[0040] Figure 10 This is an image of the light spot formed on the imaging surface by the optical system according to Embodiment 4 of this application.

[0041] Figure label:

[0042] 100. Lens group; 200. Microstructure array; 210. Microstructure; 220. Substrate;

[0043] 300, image sensor; 400, imaging surface. Detailed Implementation

[0044] In the description of the embodiments of this application, it should be noted that the terms "longitudinal," "lateral," "upper," "lower," "top," "bottom," "inner," and "outer," etc., indicate the orientation or state relationship based on the orientation or state relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0045] In the description of the embodiments of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application based on the specific circumstances.

[0046] In the embodiments of this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0047] The following description, in conjunction with the accompanying drawings, illustrates exemplary embodiments of this application, including various details to aid understanding. These should be considered merely exemplary. Therefore, those skilled in the art will recognize that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of this application. Similarly, for clarity and brevity, descriptions of well-known functions and structures are omitted in the following description.

[0048] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0049] In related technologies, optical modules typically include optical lenses and image sensors. The optical lenses consist of multiple circular lenses spaced apart along the optical axis. For example... Figure 1As shown, external light passes through each lens in sequence, forming a circular light spot that illuminates the photosensitive chip. However, some photosensitive chips are rectangular or elliptical, and along the length of the chip, the circular light spot only illuminates a portion of the photosensitive area, leaving the remaining area untouched. To avoid wasting photosensitive area, some optical lenses incorporate concave cylindrical mirrors to increase the lens's power in a specific direction, thereby altering the shape of the light spot. However, concave cylindrical mirrors affect the energy of the final light spot, leading to a decrease in light spot energy.

[0050] like Figure 2 As shown, to at least solve the above-mentioned problems, this application provides an optical system including a lens group 100 and a microstructure array 200 located on the transmission optical path of the lens group 100. The microstructure array 200 includes a plurality of microstructures 210 distributed along a first direction and a second direction, the first direction and the second direction having an included angle; the optical parameters of the microstructures 210 along the first direction satisfy preset conditions, such that the focal length of the optical system along the first direction is less than the focal length of the optical system along the second direction, the optical parameters including focal length and / or radius of curvature.

[0051] As can be seen from the above, by setting a microstructure array 200 in the transmission optical path of the lens group 100 and ensuring that the optical parameters of the microstructures 210 of the microstructure array 200 along the first direction meet preset conditions, the focal length of the entire optical system along the first direction can be reduced, making the focal length of the optical system along the first direction smaller than its focal length along the second direction. External light passes through the lens group 100 and then strikes the microstructure array 200. The light passing through the microstructures 210 first converges and then diverges, ultimately forming a light spot that is stretched and elongated along the first direction. In other words, the light spot formed on the imaging surface 400 of the optical system is an elongated strip-shaped light spot extending along the first direction. Therefore, when the optical system of this embodiment is applied to an optical module, not only can the utilization rate of the photosensitive area of ​​the photosensitive chip 300 be improved, but the energy of the light spot is not affected. Furthermore, the microstructure array 200 is easy to manufacture, has low cost, and is easy to mass-produce.

[0052] It should be noted that the optical system in the embodiments of this application may be, but is not limited to, the receiver of a lidar. Furthermore, the first direction and the second direction may or may not be perpendicular to each other. For example, as... Figure 5 , Figure 6 , Figure 8 and Figure 10As shown, the first direction is the y-axis direction, and the second direction is the x-axis direction. Alternatively, there may be an acute or obtuse angle between the first and second directions. Furthermore, the microstructure 210 can be a microlens or a nanostructure on a nanoimprint film. For example, the microstructure array 200 includes a substrate 220 and multiple microlenses, which are distributed in an array on at least one side of the substrate 220. Alternatively, the microstructure array 200 includes a substrate 220 and a nanoimprint film, with the nanoimprint film formed on at least one side of the substrate 220. Additionally, the lens group 100 may include one or more lenses. When the lens group 100 includes multiple lenses, the lenses are sequentially spaced along the optical axis from the object side to the image side. The lenses can be glass lenses or plastic lenses. If the ambient temperature is high and high resolution is required, glass lenses can be selected.

[0053] In some embodiments, the focal length Fy0 of the optical system along the first direction and the focal length Fx0 of the optical system along the second direction satisfy: Fx0 / Fy0 ≥ 1.01. Further, Fx0 / Fy0 ≥ 1.05. For example, the value of Fx0 / Fy0 can be 1.06, 1.07, 1.08, or 1.09.

[0054] This application can make the focal length of the optical system along the first direction smaller than the focal length of the optical system along the second direction by limiting the focal length and / or radius of curvature of the microstructure 210 along the first direction. The preset condition that the focal length or radius of curvature of the microstructure 210 along the first direction should satisfy may be, but is not limited to, at least one of the following:

[0055] Firstly, the focal length Fy1 of the microstructure 210 along the first direction and the focal length Fy2 of the lens group 100 along the first direction satisfy: |Fy1 / Fy2|≥1.1. Further, 1.2≤|Fy1 / Fy2|≤6. For example, the value of Fy1 / Fy2 can be 2.5, 3.5, 4.5, or 5.5. This embodiment controls the focal length of the microstructure 210 and the lens group 100 along the first direction using the above conditional formula, thereby reducing the focal length of the optical system along the first direction to be smaller than the focal length of the optical system along the second direction. This allows external light to pass through the optical system and form a long strip-shaped light spot extending along the first direction on the imaging surface 400. It should be noted that the focal length of the microstructure 210 along the first direction can be controlled by limiting the radius of curvature, material, or thickness of the microstructure 210.

[0056] The second type of focal length, Fy1 of the microstructure 210 along the first direction, the focal length Fy2 of the lens group 100 along the first direction, and the air gap d between the lens group 100 and the microstructure array 200 satisfy: 0.10 ≤ Fy2 / (Fy1*SQRT(d)). Further, 0.10 ≤ Fy2 / (Fy1*SQRT(d)) ≤ 1.15. As an example, 0.13 ≤ Fy2 / (Fy1*SQRT(d)) ≤ 0.57. For example, the value of Fy2 / (Fy1*SQRT(d)) can be 0.2, 0.3, 0.4, or 0.5. In this embodiment of the application, by controlling the focal length of the microstructure 210 and the lens group 100 along the first direction and the air gap between the lens column and the microstructure array 200 in the above-mentioned conditional control, the focal length of the optical system along the first direction can also be reduced to be smaller than the focal length of the optical system along the second direction, thereby allowing external light to form a long strip-shaped light spot extending along the first direction on the imaging surface 400 after passing through the optical system.

[0057] The third type, the microstructure array 200, includes a substrate 220 and multiple microstructures 210. Multiple microstructures 210 are arrayed on the side of the substrate 220 facing the lens group 100 and / or on the side of the substrate 220 away from the lens group 100. Each microstructure 210 has a convex surface protruding away from the substrate 220 along the optical axis of the lens group 100. The radius of curvature R of the convex surface of the microstructure 210 along a first direction and the focal length Fy0 of the optical system along the first direction satisfy: |R / Fy0|≥0.5, and further, 0.5≤|R / Fy0|≤5. For example, the value of R / Fy0 can be 1, 1.5, 2, 2.5, 3, 3.5, 4, or 4.5. In this embodiment of the application, by utilizing the above-mentioned conditional control of the radius of curvature of the convex surface of the microstructure 210 along the first direction and the focal length of the optical system along the first direction, the focal length of the optical system along the first direction can also be reduced to be smaller than the focal length of the optical system along the second direction, thereby enabling external light to form an elongated strip-shaped light spot extending along the first direction on the imaging surface 400 after passing through the optical system.

[0058] In some embodiments, the maximum aperture D of the microstructure array 200, the image height H corresponding to the maximum field of view of the optical system, and the distance BFL between the center of the image side of the microstructure array 200 and the center of the imaging surface 400 of the optical system satisfy: D*BFL / H≥5. Further, 10≤D*BFL / H≤25. For example, the value of D*BFL / H can be 13, 16, 19, 21, or 24. By controlling the maximum aperture of the microstructure array 200, the image height corresponding to the maximum field of view of the optical system, and the distance between the center of the image side of the microstructure array 200 and the center of the imaging surface 400 of the optical system, this embodiment of the application can not only control the size of the microlens array within a reasonable range, but also increase the back focal length of the optical system, thereby reducing the angle between the light rays reaching the imaging surface 400 and the optical axis, achieving a small CRA (Chief Ray Angle).

[0059] In some embodiments, the focal length F and the entrance pupil diameter ENPD of the optical system satisfy: F / ENPD ≤ 2. Further, 1.1 ≤ F / ENPD ≤ 1.6. For example, the value of F / ENPD can be 1.2, 1.3, 1.4, or 1.5. By controlling the focal length and entrance pupil diameter of the optical system, this application embodiment can achieve a small FNO (F / ENPD), increasing the light transmission of the optical system and making the elongated light spot formed on the imaging plane 400 brighter.

[0060] In some embodiments, the distance BFL between the center of the image-side surface of the microstructure array 200 and the center of the imaging surface 400 of the optical system, and the total optical length TTL of the optical system, satisfy: BFL / TTL ≥ 0.1. Further, BFL / TTL ≥ 0.2. For example, the value of BFL / TTL can be 0.25, 0.3, 0.35, or 0.4. By adjusting the distance between the center of the image-side surface of the light-controlled microstructure array 200 and the center of the imaging surface 400 of the optical system, and the total optical length of the optical system, the back focal length of the optical system can be increased. This not only provides space for the installation and focusing of optical elements such as lenses and the microstructure array 200, thus facilitating the assembly of the optical system, but also avoids interference between optical elements.

[0061] In some embodiments, the total optical length (TTL), the maximum field of view (FOV), and the image height (H) corresponding to the maximum field of view of the optical system satisfy the following condition: TTL / H / FOV ≤ 0.3. Further, TTL / H / FOV ≤ 0.15. For example, the value of TTL / H / FOV can be 0.12, 0.1, 0.08, or 0.06. By controlling the total optical length, maximum field of view, and image height of the optical system, this application embodiment can reduce the total optical length of the optical system while keeping the ratio of the maximum field of view to the image height constant, thereby achieving miniaturization of the optical system.

[0062] In some embodiments, such as Figure 3 As shown, at least two of the multiple microstructures 210 have different thicknesses along the optical axis. That is, not all microstructures 210 in the microstructure array 200 have the same thickness; at least one microstructure 210 has the largest thickness, and at least one microstructure 210 has the smallest thickness. For example, some microstructures 210 have the largest thickness, another part has the smallest thickness, and the remaining microstructures 210 have an intermediate thickness between the largest and smallest thicknesses. Alternatively, most microstructures 210 have the largest thickness, and a small portion of the remaining microstructures 210 have the smallest thickness. As an example, the difference 'a' between the largest and smallest thicknesses of a microstructure 210 is no greater than 0.1 mm. Compared to a microstructure array 200 where all microstructures 210 have the same thickness, this embodiment of the application achieves randomization of the thickness of the microstructures 210 by making at least two microstructures 210 have different thicknesses along the optical axis. This can eliminate diffraction caused by the microstructures themselves and improve imaging quality.

[0063] In addition, such as Figure 4 , Figure 7 and Figure 9 As shown, this application embodiment also provides an optical module, which includes a photosensitive chip 300 and the aforementioned optical system. The photosensitive chip 300 has a larger dimension along a first direction than its dimension along a second direction. The photosensitive chip 300 is located on the imaging surface 400 of the optical system, which is located on the side of the microstructure array 200 of the optical system away from the lens group 100.

[0064] Because the optical system in this embodiment is provided with a microstructure array 200, and the optical parameters of the microstructure 210 of the microstructure array 200 along the first direction meet the preset conditions, the focal length of the optical system along the first direction is smaller than its focal length along the second direction. Therefore, after external light passes through the lens group 100, it is directed to the microstructure array 200. The light passing through the microstructure 210 first converges and then diverges, and the light spot formed is stretched and elongated along the first direction. In other words, the light spot formed on the photosensitive chip 300 is a long strip-shaped light spot extending along the first direction. The size of the photosensitive chip 300 along the first direction is larger than its size along the second direction. That is to say, the light spot is adapted to the shape of the photosensitive chip 300. Thus, the photosensitive area of ​​the photosensitive chip 300 is almost illuminated by the light spot, whether along the first direction or the second direction. This not only improves the utilization rate of the photosensitive area of ​​the photosensitive chip 300, but also does not affect the energy of the light spot.

[0065] The following are examples illustrating optical modules with different structural forms in the embodiments of this application:

[0066] Example 1

[0067] like Figure 4 and Figure 5 As shown, the optical module in this embodiment includes an optical system and a photosensitive chip 300. The optical system includes a lens group 100 and a microstructure array 200. The microstructure array 200 is located in the transmission light path of the lens group 100, and the photosensitive chip 300 is located on the side of the microstructure array 200 away from the lens group 100 and is on the imaging surface 400 of the optical system. The photosensitive chip 300 has a larger dimension along the first direction than the photosensitive chip 300 along the second direction. The microstructure array 200 includes a substrate 220 and a plurality of microstructures 210. The plurality of microstructures 210 are arrayed along the first and second directions on the side of the substrate 220 facing the lens group 100. The surface of the microstructure 210 facing the lens group 100, i.e. the object side, is a convex surface that protrudes in a direction away from the substrate 220 along the optical axis of the lens group 100. The optical parameters of the microstructure 210 along the first direction meet preset conditions so that the focal length of the optical system along the first direction is smaller than the focal length of the optical system along the second direction. The optical parameters include focal length and / or radius of curvature. The first and second directions have an angle between them.

[0068] Furthermore, in this embodiment, at least two of the multiple microstructures 210 have different thicknesses along the optical axis, and the difference 'a' between the maximum thickness and the minimum thickness of the microstructure 210 is no greater than 0.1 mm. Compared to a microstructure array 200 where all microstructures 210 have the same thickness, this embodiment achieves randomization of the thickness of the microstructures 210 by making at least two of the microstructures 210 have different thicknesses along the optical axis. This can eliminate diffraction caused by the microstructures themselves and improve imaging quality.

[0069] Table 1 below shows the focal length Fy1 of microstructure 210 along the first direction, the focal length Fy2 of lens group 100 along the first direction, the air gap d between lens group 100 and microstructure array 200, the radius of curvature R of the object side surface of microstructure 210 along the first direction, the maximum aperture D of microstructure array 200, the image height H corresponding to the maximum field of view of optical system, the distance BFL between the center of the image side surface of microstructure array 200 and the center of imaging surface 400 of optical system, the focal length F of optical system, the entrance pupil diameter ENPD of optical system, the total optical length TTL of optical system, the maximum field of view FOV of optical system, the focal length Fy0 of optical system along the first direction, the focal length Fx0 of optical system along the second direction, and the length Ly of the elongated light spot along the first direction in Embodiment 1.

[0070] Table 1

[0071]

[0072]

[0073] Example 2

[0074] like Figure 3 and Figure 6 As shown, the optical module in this embodiment has a structure that is basically the same as that in embodiment 1. The parts that are the same as those in embodiment 1 will not be described again in this embodiment. The differences are: the focal length Fy1 of the microstructure 210 along the first direction is 45.21 mm, the radius of curvature R of the object side surface of the microstructure 210 along the first direction is 23 mm, the focal length Fy0 of the optical system along the first direction is 25.22 mm, and the length Ly of the elongated light spot along the first direction is about 220 μm.

[0075] Table 2 below shows the focal length Fy1 of microstructure 210 along the first direction, the focal length Fy2 of lens group 100 along the first direction, the air gap d between lens group 100 and microstructure array 200, the radius of curvature R of the object side surface of microstructure 210 along the first direction, the maximum aperture D of microstructure array 200, the image height H corresponding to the maximum field of view of optical system, the distance BFL between the center of the image side surface of microstructure array 200 and the center of imaging surface 400 of optical system, the focal length F of optical system, the entrance pupil diameter ENPD of optical system, the total optical length TTL of optical system, the maximum field of view FOV of optical system, the focal length Fy0 of optical system along the first direction, the focal length Fx0 of optical system along the second direction, and the length Ly of the elongated light spot along the first direction in Embodiment 1.

[0076] Table 2

[0077] parameter Fy1(mm) Fy2(mm) d(mm) R(mm) D(mm) H(mm) numerical values 45.21 34.22 2 23 21 16.05 parameter BFL (mm) F(mm) ENPD (mm) TTL(mm) FOV (°) Fy0(mm) numerical values 15.73 34.22 24.3 49.58 26.5 25.22 parameter Fx0(mm) Ly(um) numerical values 34.22 Approximately 220

[0078] Example 3

[0079] like Figure 7 and Figure 8 As shown, the optical module in this embodiment has a basically the same structure as the optical module in Embodiment 1. The parts that are the same as in Embodiment 1 will not be described again in this embodiment. The difference lies in that the microstructure array 200 includes a substrate 220 and multiple microstructures 210. The multiple microstructures 210 are arrayed along a first direction and a second direction on the side of the substrate 220 away from the lens group 100. Along the optical axis of the lens group 100, the surface of the microstructure 210 facing the photosensitive chip 300, i.e., the image-side surface, is a convex surface protruding in the direction away from the substrate 220. Specifically, the focal length Fy1 of the microstructure 210 along the first direction is 78.62 mm, the focal length Fy0 of the optical system along the first direction is 28.49 mm, the radius of curvature R of the image-side surface of the microstructure 210 along the first direction is -40 mm, and the length Ly of the elongated light spot along the first direction is approximately 140 μm.

[0080] Table 3 below shows the focal length Fy1 of microstructure 210 along the first direction, the focal length Fy2 of lens group 100 along the first direction, the air gap d between lens group 100 and microstructure array 200, the radius of curvature R of image side surface of microstructure 210 along the first direction, the maximum aperture D of microstructure array 200, the image height H corresponding to the maximum field of view of optical system, the distance BFL between the center of image side surface of microstructure array 200 and the center of imaging surface 400 of optical system, the focal length F of optical system, the entrance pupil diameter ENPD of optical system, the total optical length TTL of optical system, the maximum field of view FOV of optical system, the focal length Fy0 of optical system along the first direction, the focal length Fx0 of optical system along the second direction, and the length Ly of long strip light spot along the first direction in Embodiment 1.

[0081] Table 3

[0082] parameter Fy1(mm) Fy2(mm) d(mm) R(mm) D(mm) H(mm) numerical values 78.62 34.22 2 -40 21 16.05 parameter BFL (mm) F(mm) ENPD (mm) TTL(mm) FOV (°) Fy0(mm) numerical values 15.73 34.22 24.3 49.58 26.5 28.49 parameter Fx0(mm) Ly(um) numerical values 34.22 Approximately 140

[0083] Example 4

[0084] like Figure 9 and Figure 10 As shown, the optical module in this embodiment has a structure that is basically the same as that in embodiment 1. The parts that are the same as those in embodiment 1 will not be described again in this embodiment. The difference is that the microstructure array 200 includes a substrate 220 and a plurality of microstructures 210. The substrate 220 has a plurality of microstructures 210 arranged in an array along the first direction and the second direction on both the side of the substrate 220 facing the lens group 100 and the side of the substrate 220 away from the lens group 100. The object side of the microstructure 210 located between the substrate 220 and the lens group 100, that is, the surface facing the lens group 100, is a convex surface that protrudes in the direction away from the substrate 220 along the optical axis. The image side of the microstructure 210 located between the substrate 220 and the photosensitive chip 300, that is, the surface facing the photosensitive chip 300, is a convex surface that protrudes in the direction away from the substrate 220 along the optical axis. Among them, the focal length Fy1 of the microstructure 210 along the first direction is 67.47 mm, the focal length Fy0 of the optical system along the first direction is 28.00 mm, the distance BFL between the center of the image side of the microstructure array 200 and the center of the imaging surface 400 of the optical system is 14.73 mm, the image height H corresponding to the maximum field of view of the optical system is 16.04 mm, the radius of curvature R of the object side of the microstructure 210 located between the substrate 220 and the lens group 100 and the image side of the microstructure 210 located between the substrate 220 and the photosensitive chip 300 along the first direction is 60 mm and -80 mm, respectively, the air gap d between the lens group 100 and the microstructure array 200 is 3 mm, and the length Ly of the elongated light spot along the first direction is about 130 μm.

[0085] Table 4 below shows the following parameters in Embodiment 1: focal length Fy1 of microstructure 210 along the first direction, focal length Fy2 of lens group 100 along the first direction, air gap d between lens group 100 and microstructure array 200, radius of curvature R of object side of microstructure 210 located between substrate 220 and lens group 100 along the first direction, radius of curvature R of image side of microstructure 210 located between substrate 220 and photosensitive chip 300 along the first direction, maximum aperture D of microstructure array 200, image height H corresponding to maximum field of view of optical system, distance BFL between center of image side of microstructure array 200 and center of imaging surface 400 of optical system, focal length F of optical system, entrance pupil diameter ENPD of optical system, total optical length TTL of optical system, maximum field of view FOV of optical system, focal length Fy0 of optical system along the first direction, focal length Fx0 of optical system along the second direction, and length Ly of elongated light spot along the first direction.

[0086] Table 4

[0087] parameter Fy1(mm) Fy2(mm) d(mm) R / object side (mm) R / Image side (mm) D(mm) numerical values 67.47 34.22 3 60 -80 21 parameter BFL (mm) F(mm) ENPD (mm) TTL(mm) FOV (°) Fy0(mm) numerical values 14.73 34.22 24.3 49.58 26.5 28.00 parameter Fx0(mm) Ly(um) H(mm) numerical values 34.22 Approximately 130 16.04

[0088] In summary, Examples 1 to 4 satisfy the relationships shown in Table 5 below.

[0089] Table 5

[0090]

[0091] As shown in Table 5, in Examples 1 to 4, |Fy1 / Fy2|≥1.1, 0.10≤Fy2 / (Fy1*SQRT(d)), and |R / Fy0|≥0.5. This application controls the relative magnitudes of the focal lengths of the microstructure 210 and lens group 100 along the first direction, the relative magnitudes of the air gaps between the lens column and the microstructure array 200, the radius of curvature of the convex surface of the microstructure 210 along the first direction, and the relative magnitudes of the focal lengths of the optical system along the first direction using the above three conditional expressions. This reduces the focal length of the optical system along the first direction to be smaller than the focal length along the second direction, thereby causing external light to pass through the optical system and form a long strip-shaped light spot extending along the first direction on the imaging surface 400.

[0092] Furthermore, according to Table 5, D*BFL / H≥5, F / ENPD≤2, BFL / TTL≥0.1, and TTL / H / FOV≤0.3. It is evident that the size of the microstructure array 200 in this application is within a reasonable range. With D*BFL / H≥5, the optical system has a large back focal length, thereby reducing the angle between the light rays reaching the imaging plane 400 and the optical axis, achieving a small CRA. With F / ENPD≤2, a small FNO can be achieved, further increasing the light transmission of the optical system and improving the brightness of the elongated light spot. With BFL / TTL≥0.1, the back focal length of the optical system can also be increased, reserving space for the installation and focusing of optical components such as the lens and microstructure array 200. With TTL / H / FOV≤0.3, the total optical length of the optical system can be reduced while maintaining the ratio of the maximum field of view to the image height corresponding to the maximum field of view, achieving miniaturization of the optical system.

[0093] In addition, this application also provides a method for mounting an optical module, the method comprising:

[0094] S100. Along the object side to the image side of the lens barrel, the microstructure array 200 and the lens group 100 are sequentially installed into the lens barrel to form an optical system.

[0095] S200, Fix the photosensitive chip 300 onto the surface of the circuit board;

[0096] S300. Fix the lens barrel to the circuit board and place the lens barrel cover on the photosensitive chip 300.

[0097] The microstructure array 200 includes multiple microstructures distributed along a first direction and a second direction. The optical parameters of the microstructures along the first direction meet preset conditions so that the focal length of the optical system along the first direction is less than the focal length of the optical system along the second direction. The optical parameters include focal length and / or radius of curvature. The photosensitive chip 300 has a larger dimension along the first direction than its dimension along the second direction. The first direction and the second direction have an angle between them.

[0098] It should be noted that, unless explicitly specified or contradicted by the context, the specific steps included in the above installation method are not limited to the order in which they are described, but can be executed in any order or in parallel.

[0099] The specific embodiments described above do not constitute a limitation on the scope of protection of this application. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. An optical system characterized by, The optical system comprises: a lens group; and a microstructure array located on a transmission light path of the lens group, the microstructure array comprising a plurality of microstructures distributed along a first direction and a second direction, the first direction and the second direction having an included angle; wherein an optical parameter of the microstructure along the first direction satisfies a preset condition, so that a focal length of the optical system along the first direction is smaller than a focal length of the optical system along the second direction, the optical parameter comprising a focal length and / or a radius of curvature; wherein the microstructure array further comprises a substrate, a side of the substrate facing the lens group and / or a side of the substrate away from the lens group being arrayed with a plurality of the microstructures; along an optical axis direction of the lens group, the microstructure has a convex surface protruding in a direction away from the substrate; wherein the preset condition comprises that a radius of curvature R of the convex surface along the first direction and a focal length Fy0 of the optical system along the first direction satisfy: 0.5≤|R / Fy0|≤5; wherein a focal length Fy0 of the optical system along the first direction and a focal length Fx0 of the optical system along the second direction satisfy: Fx0 / Fy0≥1.

01.

2. The optical system of claim 1, wherein, The preset condition comprises that a focal length Fy1 of the microstructure along the first direction and a focal length Fy2 of the lens group along the first direction satisfy: |Fy1 / Fy2|≥1.

1.

3. The optical system of claim 1, wherein, The preset condition comprises that the focal length Fy1 of the microstructure along the first direction, the focal length Fy2 of the lens group along the first direction, and an air gap d between the lens group and the microstructure array satisfy: 0.10 mm -1 / 2 ≤ Fy2 / (Fy1 SQRT(d)).

4. The optical system according to any one of claims 1 to 3, wherein, A maximum aperture D of the microstructure array, an image height H corresponding to a maximum field of view angle of the optical system, and a distance BFL between a center of an image side surface of the microstructure array and a center of an imaging surface of the optical system satisfy: D BFL / H ≥ 5 mm.

5. The optical system according to any one of claims 1 to 3, wherein, A focal length F of the optical system and an entrance pupil diameter ENPD of the optical system satisfy: F / ENPD≤2.

6. The optical system according to any one of claims 1 to 3, wherein, The distance BFL between the center of the image side surface of the microstructure array and the center of the imaging surface of the optical system and a total optical length TTL of the optical system satisfy: BFL / TTL≥0.

1.

7. The optical system according to any one of claims 1 to 3, wherein, The total optical length TTL of the optical system, a maximum field of view angle FOV of the optical system, and an image height H corresponding to the maximum field of view angle of the optical system satisfy: TTL / H / FOV 1° ≤ 0.

3.

8. The optical system of any one of claims 1 to 3, wherein, A thickness of at least two of the plurality of microstructures along an optical axis direction is different.

9. The optical system of claim 8, wherein, A difference between a maximum thickness of the microstructure and a minimum thickness of the microstructure is not greater than 0.1 mm.

10. The optical system of any one of claims 1 to 3, wherein, The optical system satisfies any one of the following conditional expressions: 1.2 < |Fy1 / Fy2| < 6; 0.10 mm -1 / 2 ≤ Fy2 / (Fy1 SQRT(d)) < 1.15 mm -1 / 2 ; 0.13 mm -1 / 2 ≤ Fy2 / (Fy1 SQRT(d)) < 0.57 mm -1 / 2 ; 0.91 < |R / Fy0| < 2.86; Fx0 / Fy0 > 1.05; 1.05 < Fx0 / Fy0 < 1.36; 10 mm < D BFL / H < 25 mm; 1.1 < F / ENPD < 1.6; BFL / TTL > 0.2; 0.2 < BFL / TTL < 0.4; TTL / H / FOV 1° < 0.15; 0.06 < TTL / H / FOV 1° < 0.15; Wherein, Fy1 is the focal length of the microstructure along the first direction, Fy2 is the focal length of the lens group along the first direction, d is the air gap between the lens group and the microstructure array, R is the radius of curvature of the convex surface along the first direction, Fy0 is the focal length of the optical system along the first direction, Fx0 is the focal length of the optical system along the second direction, D is the maximum aperture of the microstructure array, H is the image height corresponding to the maximum field of view of the optical system, BFL is the distance between the center of the image side of the microstructure array and the center of the imaging surface of the optical system, F is the focal length of the optical system, ENPD is the entrance pupil diameter of the optical system, TTL is the total optical length of the optical system, and FOV is the maximum field of view of the optical system.

11. An optical module characterized by comprising: include: The photosensitive chip has a dimension along the first direction that is larger than its dimension along the second direction; as well as The optical system according to any one of claims 1 to 10, wherein the photosensitive chip is located on the imaging surface of the optical system, and the imaging surface is located on the side of the microstructure array of the optical system away from the lens group.

12. A method of mounting an optical module, characterized by: include: The microstructure array and lens group are sequentially installed into the lens barrel along the object side to the image side to form an optical system; The photosensitive chip is fixed to the surface of the circuit board; as well as The lens barrel is fixed to the circuit board and the lens barrel is placed on the photosensitive chip; The microstructure array includes multiple microstructures distributed along a first direction and a second direction. The optical parameters of the microstructures along the first direction satisfy a preset condition, such that the focal length of the optical system along the first direction is less than the focal length of the optical system along the second direction. The optical parameters include focal length and / or radius of curvature. The size of the photosensitive chip along the first direction is greater than its size along the second direction, and the first direction and the second direction have an angle between them. The microstructure array further includes a substrate, on which a plurality of the microstructures are arrayed in an array on one side facing the lens group and / or the side away from the lens group; along the optical axis of the lens group, the microstructures have a convex surface that protrudes away from the substrate; The preset conditions include the radius of curvature R of the convex surface along the first direction and the focal length Fy0 of the optical system along the first direction satisfying: 0.5≤|R / Fy0|≤5; Wherein, the focal length Fy0 of the optical system along the first direction and the focal length Fx0 of the optical system along the second direction satisfy: Fx0 / Fy0≥1.01.

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