A microlens array, a lens, and an optical device
By randomly arranging lens groups and filling single lenses, the interference fringe problem in the combination of microlens arrays was solved, and high-quality light field effects were achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- JIAXING UPHOTON OPTOELECTRONICS TECH CO LTD
- Filing Date
- 2023-03-13
- Publication Date
- 2026-06-02
AI Technical Summary
When existing microlens arrays are combined with vertical cavity surface-emitting lasers or liquid crystal silicon, obvious interference fringes or water ripples appear, affecting imaging quality and visual experience.
By randomly arranging the lens groups and filling the spaces between them with single lenses, the periodic structure of the microlens array is disrupted, and interference fringes are eliminated through random arrangement.
It effectively reduces the loss of high-frequency components, eliminates interference fringes, improves the quality of the light field, enhances the light field angle, and maintains the original appearance of the light field.
Smart Images
Figure CN116430488B_ABST
Abstract
Description
Technical Field
[0001] This application relates generally to the field of micro-nano optics technology, and more specifically to a microlens array, optical system, lens, and optical device. Background Technology
[0002] Microlens arrays (MLAs) are arrays of lenses with apertures and relief depths in the micrometer range. They have a wide range of applications, such as beam shaping, optical communication, 3D sensing, and head-up displays (HUDs). However, arrayed MLAs share periodic similarities with similarly arrayed vertical-cavity surface-emitting lasers (VCSELs), liquid crystal on silicon (LCOS), and digital micromirror devices (DMDs). Combining these arrays can lead to noticeable interference fringes or ripple effects (such as...). Figure 1 As shown in the figure, this has a negative impact on its application.
[0003] For example, TOF (Time of Flight) technology can perform three-dimensional perception and distance measurement. The optical part of the TOF device is mainly divided into three parts: laser array light source, homogenizing structure and TOF lens. Usually, microlens array is used as homogenizing structure to expand and homogenize the laser beam. However, as mentioned above, the current microlens array has aperture diffraction, which causes interference fringes in the image, affecting the image quality and visual experience.
[0004] Therefore, there is a need to improve a microlens array, lens, and optical device to at least partially solve the above-mentioned technical problems. Summary of the Invention
[0005] This application is made to address at least one of the aforementioned problems. Specifically, a first aspect of this application provides a microlens array, the microlens array comprising:
[0006] Multiple lens groups are randomly positioned within the microlens array. Each lens group comprises M queues arranged along a first direction, and each queue is formed by N first lenses arranged along a second direction. The first direction is orthogonal to the second direction. The M×N first lenses in the lens group do not overlap, and adjacent first lenses in the lens group are in contact with each other. M and N are integers greater than or equal to 2. The shape of the first lens is a conventional curved surface approximated or directly processed by a multi-step structure.
[0007] A plurality of second lenses, the second lenses filling the gaps between the plurality of lens groups;
[0008] When a laser beam is incident on the microlens array, the incident light is modulated by the microlens array to disrupt the periodic structure of the microlens array as a whole by using randomization, thereby eliminating interference fringes.
[0009] According to the microlens array of this application, by randomly arranging the lens groups and filling the gaps between the lens groups with single lenses, the loss of high-frequency components is reduced. Furthermore, the random arrangement disrupts the overall periodic structure, which can achieve the effect of eliminating interference fringes while obtaining a larger light field.
[0010] Optionally, at least a portion of the lens group is parallel to the second direction; and / or
[0011] At least some of the lens groups are not parallel between their second directions.
[0012] Optionally, at least some of the second directions of the lens group are not parallel to each other, and at least some of the second directions of the lens group have a first included angle.
[0013] Optionally, the degree of the first included angle is less than or equal to 20°.
[0014] Optionally, the microlens array has multiple partitions, each partition having multiple lens groups, the second directions of the multiple lens groups in one partition being parallel, and the second directions of the lens groups in different partitions having a second included angle.
[0015] Optionally, the degree of the second included angle is less than or equal to 10°.
[0016] Optionally, the microlens array has a first central plane, and the microlens array is symmetrical with respect to the first central plane;
[0017] The second included angle between the second direction of the lens group in the plurality of partitions and the second direction of the lens group closest to the first central plane gradually increases in a direction away from the first central plane.
[0018] Optionally, the microlens array has a second central plane, which is perpendicular to the first central plane, and the microlens array is symmetrical with respect to the second central plane.
[0019] Optionally, at least one group of adjacent queues are misaligned along the second direction.
[0020] Optionally, the size of the misalignment does not exceed half the aperture of the first lens.
[0021] Optionally, in the microlens array, the area of the overlapping portion occupies less than or equal to 20% of the total area.
[0022] Optionally, the area of the plurality of said lens groups occupies a ratio of 60% or more of the total area.
[0023] Optionally, the aperture of the second lens is the same as that of the first lens.
[0024] Optionally, the surface profile of the second lens is the shape of the area where the four first lenses in the 2×2 subarray of the lens group are connected to each other.
[0025] Optionally, at least some of the lens groups have different surface shapes for their first lenses.
[0026] Optionally, at least a portion of the edges of the first lens and / or the second lens are straight edges and / or curved edges.
[0027] Optionally, the M×N first lenses in one of the lens groups have the same surface shape.
[0028] A second aspect of this application provides a lens comprising the microlens array described in the first aspect above.
[0029] The lens of this application, because it includes the aforementioned microlens array, has advantages that are substantially similar to those of a microlens array.
[0030] A third aspect of this application provides an optical device comprising the microlens array described in the first aspect; or
[0031] The optical device includes the lens described in the third aspect above.
[0032] The optical device of this application, because it includes the aforementioned lens or microlens array, has advantages that are substantially similar to those of a lens or microlens array. Attached Figure Description
[0033] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0034] Figure 1 This is a square test result diagram of a regularly arranged microlens array in the prior art;
[0035] Figure 2A schematic diagram of the arrangement structure of a microlens array according to one embodiment of this application is shown;
[0036] Figure 3 A schematic diagram of the overall arrangement structure of the microlens array according to one embodiment of this application is shown;
[0037] Figure 4a A schematic diagram of a 2×2 lens group according to one embodiment of this application is shown;
[0038] Figure 4b A schematic diagram showing a misalignment of a 2×2 lens group according to one embodiment of this application is provided.
[0039] Figure 5 A schematic diagram of the arrangement structure of a microlens array according to another embodiment of this application is shown;
[0040] Figure 6a A schematic diagram of a 3×3 lens group according to one embodiment of this application is shown;
[0041] Figure 6b A schematic diagram of a misalignment configuration of a 3×3 lens group according to one embodiment of this application is shown;
[0042] Figure 6c A schematic diagram of another misalignment of a 3×3 lens group according to one embodiment of this application is shown;
[0043] Figure 7 A schematic diagram showing the rotation of the lens group and the second lens part of the microlens array in Figure 4 is shown.
[0044] Figure 8 A schematic diagram of the arrangement structure of a microlens array according to another embodiment of this application is shown;
[0045] Figure 9 The light field test diagrams of the microlens array, which uses a 2×2 lens group, are shown; and
[0046] Figure 10 The light field test diagram of the microlens array, which uses a 3×3 lens group, is shown. Detailed Implementation
[0047] To make the objectives, technical solutions, and advantages of this application more apparent, exemplary embodiments according to this application will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of this application, and not all embodiments of this application. It should be understood that this application is not limited to the exemplary embodiments described herein. Based on the embodiments of this application described herein, all other embodiments obtained by those skilled in the art without inventive effort should fall within the protection scope of this application.
[0048] The following description provides numerous specific details to offer a more thorough understanding of this application. However, it will be apparent to those skilled in the art that this application can be practiced without one or more of these details. In other instances, certain technical features well-known in the art have not been described to avoid confusion with this application.
[0049] It should be understood that this application can be implemented in various forms and should not be construed as being limited to the embodiments set forth herein. Rather, providing these embodiments will make the disclosure thorough and complete, and will fully convey the scope of this application to those skilled in the art.
[0050] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of this application. When used herein, the singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising” and / or “including,” when used in this specification, identify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups. When used herein, the term “and / or” includes any and all combinations of the associated listed items.
[0051] To fully understand this application, a detailed structure will be presented in the following description to illustrate the technical solution proposed in this application. Optional embodiments of this application are described in detail below; however, in addition to these detailed descriptions, this application may have other implementation methods.
[0052] To solve the aforementioned technical problems, please refer to the appendix. Figures 2 to 9 The first aspect of this application provides a microlens array comprising multiple lens groups and multiple second lenses 120. The multiple lens groups are randomly positioned within the microlens array. Each lens group comprises M queues 112 arranged along a first direction L1, and each queue 112 is formed by N first lenses 111 arranged along a second direction L2. The first direction L1 and the second direction L2 are orthogonal. The M×N first lenses 111 in each lens group do not overlap, and adjacent first lenses 111 in each lens group are in contact with each other. M and N are integers greater than or equal to 2. The first lenses 111 are shaped as conventional curved surfaces formed by a multi-step structure approximation process or direct fabrication. The second lenses 120 fill the gaps between the multiple lens groups. When a laser is incident on the microlens array, the incident light is modulated by the microlens array to disrupt the overall periodic structure of the microlens array using the randomized arrangement, thereby eliminating interference fringes.
[0053] According to the microlens array of this application, by randomly arranging the lens groups and filling the gaps between the lens groups with single lenses, the loss of high-frequency components is reduced. Furthermore, the random arrangement disrupts the overall periodic structure, which can achieve the effect of eliminating interference fringes while obtaining a larger light field.
[0054] The aforementioned multi-step structure approximation process can be a process of decomposing a curved surface into multiple tiny steps and then forming the steps into a curved surface step by step. For example, multiple steps can be formed by photolithography, grayscale exposure, laser direct writing, or 3D printing to combine them into a curved surface. The aforementioned direct processing can be, for example, forming a curved surface through traditional grinding, or by directly forming a curved surface by irradiating a semi-solid or liquid material with modulated light of a specific wavelength. The aforementioned conventional curved surface can refer to a surface that can be expressed by a mathematical formula, or it can be a surface fitted between ensemble mathematical expressions.
[0055] In order to obtain more high-frequency components, that is, to retain more large-angle light field information, the ratio of the area of multiple lens groups to the total area is preferably greater than or equal to 60%.
[0056] In a microlens array, different lens groups can overlap, different second lenses 120 can overlap, and lens groups and second lenses 120 can also overlap. Alternatively, different lens groups may not overlap, but different second lenses 120 can overlap, and lens groups and second lenses 120 can also overlap. The area of the overlapping portion occupies less than or equal to 20% of the total area, preferably less than or equal to 10%. Therefore, by controlling the total area of the overlapping portion, the transformation of the projected light field from square to rounded corners caused by high-frequency energy loss at the lens edges can be reduced, thus enhancing non-periodicity while maintaining the original square shape of the projected light field as much as possible.
[0057] The aperture of the second lens 120 is preferably the same as that of the first lens 111. In one alternative embodiment, the surface shape of the second lens 120 is the same as that of the first lens 111. Alternatively, the surface shape of the second lens 120 may be different from that of the first lens 111.
[0058] Furthermore, the surface shapes of the M×N first lenses 111 in a lens group are preferably identical. At least some of the first lenses 111 in multiple lens groups may have different surface shapes; that is, the first lenses 111 in different lens groups may be different.
[0059] At least a portion of the edge of the first lens 111 may be a straight edge and / or a curved edge. At least a portion of the edge of the second lens 120 may also be a straight edge and / or a curved edge.
[0060] In one alternative implementation, M and N are unequal integers, i.e., M ≠ N. Exemplarily, the lens group can be a 2×3 lens group, a 2×4 lens group, a 2×5 lens group, a 3×4 lens group, a 3×5 lens group, a 4×5 lens group, and a 5×6 lens group, or combinations thereof.
[0061] Preferably, M and N are equal integers. In other words, the aforementioned multiple lens groups can be a 2×2 lens group 110, a 3×3 lens group 210, a 4×4 lens group, a 5×5 lens group, or a combination thereof. For example, refer to... Figure 2 and Figure 3 A schematic diagram of a microlens array 100, where all lens groups are 2×2 lens groups 110, is shown. (Reference) Figure 5 A schematic diagram of a microlens array 200 consisting of multiple 2×2 lens groups 110 and multiple 3×3 lens groups 210 arranged randomly is shown.
[0062] The form of the lens group can be referenced. Figure 4a , Figure 4b , Figure 6a , Figure 6b , Figure 6c .in, Figure 4a and Figure 6a The 2×2 lens group 110 and the 3×3 lens group 210 are shown respectively. Figure 4a In this configuration, two first lenses 111 are arranged along the second direction L2 to form a row 112, and two rows 112 are arranged along the first direction L1 to form a 2×2 lens group 110. Figure 6a Three first lenses 111 are arranged along the second direction L2 to form a queue 112, and three queues 112 are arranged along the first direction L1 to form a 3×3 lens group 210.
[0063] As one implementation, at least one pair of adjacent rows 112 in the lens group are misaligned along the second direction L2, thereby increasing the sharp area in the lens group and further increasing the high-frequency components. Preferably, the size of the misalignment does not exceed half the aperture of the first lens 111, so as not to cause loss of high-frequency components due to excessive misalignment. For example, see reference... Figure 4b The misalignment of the two queues 112 in the 2×2 lens group 110 is shown. Figure 6b and Figure 6c Two misalignment patterns of the three rows 112 in the 3×3 lens group 210 are shown respectively, in which Figure 6b The middle queue 112 of the 3×3 lens group 210 is misaligned relative to the queues 112 on both sides. Figure 6c The three columns 112 of the 3×3 lens group 210 form a stepped misalignment.
[0064] To further obtain high-frequency components and retain a larger optical field angle, the surface shape of the second lens 120 is the shape of the area where the four first lenses 111 in the 2×2 sub-array of the lens group are connected to each other, as shown in the figure. Figure 4a and Figure 4b The 2×2 lens group 110 has the shape of the region within the dashed box. Alternatively, the surface profile of the second lens 120 is constructed to resemble the shape of the region where the four first lenses 111 in the 3×3 sub-array of the lens group are connected to each other, as shown below. Figure 6a , Figure 6b and Figure 6c One of the 3×3 lens groups 210 has the shape of the area within the four dashed boxes.
[0065] In one alternative embodiment, at least a portion of the lens group is parallel in the second direction L2. Preferably, reference... Figure 2 , Figure 3 and Figure 5 All lens groups 210 are parallel in the second direction L2. In other words, the aforementioned "random position" here refers to the random arrangement of lens groups 210 while restricting their rotation.
[0066] In another alternative embodiment, at least some of the lens groups are not parallel in their second directions L2. (See reference) Figure 7 The diagram shows a microlens array 300 in which multiple 2×2 lens groups 110 and multiple 3×3 lens groups 210 are randomly arranged. In addition to the random arrangement of the lens groups, some of the lens groups can also be rotated.
[0067] In an embodiment not shown, all lens groups can be rotated at a certain angle. This further reduces the periodicity of the microlens array.
[0068] Preferably, the rotation angle is -10° to 10°. More preferably, it is -5° to 5°, that is, a maximum clockwise rotation of 5° or a maximum counterclockwise rotation of 5°. It can also be understood that at least a portion of the lens group has a first included angle between the second directions L2. The degree of the first included angle is less than or equal to 20°, preferably less than or equal to 10°. Thus, by using a small rotation of the lens group to further reduce the periodicity of the microlens array, the optical field compensation is not compromised due to excessive rotation.
[0069] In yet another alternative implementation, refer to Figure 8 The microlens array 400 has multiple partitions, each partition is provided with multiple lens groups 110, the second direction L2 of the multiple lens groups 110 in one partition is parallel, and the second direction L2 of the lens groups 110 in different partitions has a second included angle.
[0070] The microlens array 400 has a first central plane P1 and a second central plane P2, with the first central plane P1 and the second central plane P2 being perpendicular. The microlens array 100 is symmetrical with respect to the first central plane P1, and the microlens array 400 is symmetrical with respect to the second central plane P2.
[0071] The second angle of the second direction L2 of the lens group 110 in the plurality of partitions relative to the second direction L2 of the lens group 110 closest to the first central plane P1 gradually increases in the direction away from the first central plane P1. Preferably, the second angle of the second direction L2 of the lens group 110 between two adjacent partitions is less than 10°. More preferably, the second angle of the second direction L2 of the lens group 110 between two adjacent partitions is less than 5°.
[0072] exist Figure 8 In the illustrated embodiment, along a direction away from the first central plane P1, the microlens array 400 sequentially has a first partition 101, a second partition 102, a third partition 103, and a fourth partition 104. Furthermore, the second included angle between the second partition 102 and the first partition 101 is smaller than the second included angle between the third partition 103 and the first partition 101, and the second included angle between the third partition 103 and the first partition 101 is smaller than the second included angle between the fourth partition 104 and the first partition 101.
[0073] Based on the above settings, the corner energy can be compensated to prevent it from becoming too low, and the periodicity of the arrangement can be further reduced, thus lowering the possibility of water ripples. Furthermore, different zones can be arranged with second lenses and / or lens groups with different functions, thereby enabling combinations of different functions and providing greater design flexibility.
[0074] refer to Figure 9 and Figure 10 The two images respectively show the light field test diagrams of a microlens array using only 2×2 lens groups 110 according to an embodiment of this application, and the light field test diagrams of a microlens array using only 3×3 lens groups 210 according to an embodiment of this application. (Comparison) Figure 1 , Figure 9 and Figure 10 It is evident that the light field test pattern according to the embodiment of this application has eliminated interference fringes, no water ripple phenomenon has appeared, and compared with the regularly arranged... Figure 1 The light field angle does not change significantly in the embodiments of this application.
[0075] The design method of the above microlens array will be introduced below:
[0076] The first step is to randomly arrange multiple lens groups that are slightly smaller than the standard size while restricting rotation, without any overlap during the arrangement process;
[0077] The second step is to fill the gaps between the above lens groups with standard-sized single lenses, such that the single lens has at most 10% overlap with the above lens groups.
[0078] The third step is to fill the gap area after the above two steps with a single lens that is slightly smaller than the standard size, so that the smaller single lens has at most 20% overlap with the standard single lens and / or lens group.
[0079] The fourth step is to expand the smaller lens group and / or the smaller single lens to restore them to their standard size and fill all the gaps to ensure that there are no light leakage areas.
[0080] Preferably, the smaller lens group and / or the smaller single lens can be finely adjusted by angular rotation before the expansion operation in the fourth step.
[0081] A second aspect of this application provides a lens comprising the microlens array described in the first aspect above.
[0082] The lens of this application, because it includes the aforementioned microlens array, has advantages that are substantially similar to those of a microlens array.
[0083] A third aspect of this application provides an optical device, including the lens described in the third aspect or the microlens array described in the first aspect.
[0084] The optical device of this application, because it includes the aforementioned lens or microlens array, has advantages substantially similar to those of a lens or microlens array. The aforementioned optical device can be a HUD or TOF, etc.
[0085] It should be noted that the above embodiments are illustrative of this application and not limiting of it, and that those skilled in the art can devise alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses should not be construed as limiting the claims. This application can be implemented by means of hardware comprising several different elements and by means of a suitably programmed computer. In the unit claims enumerating several means, several of these means may be embodied by the same item of hardware. The use of the words first, second, and third, etc., does not indicate any order. These words can be interpreted as names.
Claims
1. A microlens array, characterized in that, The microlens array includes: Multiple lens groups are randomly positioned within the microlens array. Each lens group comprises M queues arranged along a first direction of itself. Each queue consists of N first lenses arranged along a second direction of itself. The first direction and the second direction of each lens group are orthogonal. The M×N first lenses in each lens group do not overlap, and adjacent first lenses in each lens group are in contact with each other. M and N are integers greater than or equal to 2. The shape of the first lens is a conventional curved surface approximated or directly processed by a multi-step structure. A plurality of second lenses, the second lenses filling the gaps between the plurality of lens groups; When a laser beam is incident on the microlens array, the incident light is modulated by the microlens array to disrupt the periodic structure of the microlens array as a whole by using randomization, thereby eliminating interference fringes.
2. The microlens array according to claim 1, characterized in that, At least a portion of the lens group is parallel to the second direction; and / or At least some of the lens groups are not parallel between their second directions.
3. The microlens array according to claim 1, characterized in that, At least some of the lens groups have second directions that are not parallel to each other, and at least some of the lens groups have second directions that have a first included angle to each other.
4. The microlens array according to claim 3, characterized in that, The degree measure of the first included angle is less than or equal to 20°.
5. The microlens array according to claim 1, characterized in that, The microlens array has multiple partitions, and each partition is provided with multiple lens groups. The second directions of the multiple lens groups in a partition are parallel, and the second directions of the lens groups in different partitions are at a second angle.
6. The microlens array according to claim 5, characterized in that, The second included angle is less than or equal to 10°.
7. The microlens array according to claim 5, characterized in that, The microlens array has a first central plane, and the microlens array is symmetrical with respect to the first central plane; The second angle between the second direction of the lens group in the plurality of partitions and the second direction of the lens group closest to the first central plane gradually increases in a direction away from the first central plane.
8. The microlens array according to claim 7, characterized in that, The microlens array has a second central plane, which is perpendicular to the first central plane, and the microlens array is symmetrical with respect to the second central plane.
9. The microlens array according to claim 1, characterized in that, At least one group of adjacent queues are misaligned along the second direction.
10. The microlens array according to claim 9, characterized in that, The size of the misalignment does not exceed half the aperture of the first lens.
11. The microlens array according to claim 1, characterized in that, In the microlens array, the ratio of the area of the overlapping portion to the total area is less than or equal to 20%.
12. The microlens array according to claim 1, characterized in that, The area of the plurality of said lens groups occupies a ratio of 60% or more of the total area.
13. The microlens array according to any one of claims 1-12, characterized in that, The aperture of the second lens is the same as that of the first lens.
14. The microlens array according to any one of claims 1-12, characterized in that, The surface profile of the second lens is the shape of the area where the four first lenses in the 2×2 subarray of the lens group are connected to each other.
15. The microlens array according to any one of claims 1-12, characterized in that, The surface shape of the first lens in at least a portion of the multiple lens groups is different.
16. The microlens array according to any one of claims 1-12, characterized in that, At least a portion of the edges of the first lens and / or the second lens are straight edges and / or curved edges.
17. The microlens array according to any one of claims 1-12, characterized in that, The M×N first lenses in one of the lens groups have the same surface shape.
18. A lens, characterized in that, Includes the microlens array according to any one of claims 1-17.
19. An optical device, characterized in that, The optical device comprises a microlens array according to any one of claims 1-17; or The optical device includes the lens according to claim 18.