Microlens array, optical system, lens and optical device

Abstract

The application provides a microlens array, an optical system, a lens and an optical device. The microlens array comprises at least one lens group, the lens group comprises a plurality of sub-lenses arranged in sequence, and adjacent sub-lenses contact each other; in one lens group, the projection of each sub-lens on a plane parallel to the microlens array has a closed shape with a plurality of edges, the plurality of edges comprises different first shape features and second shape features, the plurality of sub-lenses form a plurality of rows and columns, and the plurality of sub-lenses in the rows and columns are arranged along a first direction or a second direction, the first direction is opposite to the second direction. The plurality of rows and columns comprise a first row and column and a second row and column, and the first row and column and the second row and column are alternately arranged along a third direction or a fourth direction, the third direction is opposite to the fourth direction, and the first direction is perpendicular to the third direction. In the first row and column, the first shape features are located in front of the second shape features along the first direction, and in the second row and column, the first shape features are located in front of the second shape features.

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] Time of Flight (TOF) technology can perform three-dimensional perception and distance measurement. The optical part of TOF is mainly divided into three parts: laser array light source, homogenizing structure and TOF lens. Microlens arrays are usually used as homogenizing structures to expand and homogenize the laser beam. However, current microlens arrays have aperture diffraction, which causes diffraction fringes in the image, affecting the image quality and visual experience.

[0003] Therefore, there is a need to improve a microlens array, optical system, lens, and optical device to at least partially solve the above-mentioned technical problems. Summary of the Invention

[0004] This application is made to address at least one of the aforementioned problems. Specifically, a first aspect of this application provides a microlens array comprising at least one lens group, the lens group comprising a plurality of sub-lenses arranged sequentially, with adjacent sub-lenses in contact with each other;

[0005] In one of the lens groups, each of the sub-lenses has a closed shape in its projection onto a plane parallel to the microlens array. The closed shape has multiple sides, which include a first shape feature and a second shape feature, wherein the first shape feature is different from the second shape feature.

[0006] In one of the lens groups, a plurality of the sub-lenses form a plurality of rows and columns, and the plurality of the sub-lenses in the rows and columns are arranged along a first direction or a second direction, wherein the first direction is opposite to the second direction;

[0007] The plurality of rows and columns include a first row and a second row and column, wherein the first row and the second row and column are arranged alternately along a third direction or a fourth direction, wherein the third direction is opposite to the fourth direction and the first direction is perpendicular to the third direction;

[0008] In the first row and column, along the first direction, the first shape feature is located in front of the second shape feature;

[0009] In the second row and column, along the first direction, the second shape feature is located in front of the first shape feature.

[0010] Optionally, in one of the lens groups, each of the sub-lenses has the same shape, and the closed shape has a first side and a second side disposed opposite to each other along the first direction or the second direction, the first side and the second side having the same shape and / or size.

[0011] Optionally, the closed shape has a third side and a fourth side connected to each other, the third side being connected to the first side and the fourth side being connected to the second side, wherein the third side and the fourth side have different shapes and / or sizes;

[0012] The first shape feature includes a third side, and the second shape feature includes a fourth side.

[0013] Optionally, the closed shape has a fifth side and a sixth side connected to each other, the fifth side being connected to the first side and the sixth side being connected to the second side, wherein the fifth side and the sixth side have different shapes and / or sizes;

[0014] Wherein, the first shape feature includes the fifth side, and the second shape feature includes the sixth side;

[0015] The first side, the second side, the third side, the fourth side, the fifth side, and the sixth side together form the closed shape.

[0016] Optionally, the fifth side and the third side have an axis of symmetry arranged along the first direction or the second direction, and the sixth side and the fourth side have an axis of symmetry arranged along the first direction or the second direction.

[0017] Optionally, the length of the third side is less than the length of the fourth side.

[0018] Optionally, the third side is constructed as a straight side, and the fourth side is constructed as a curved side.

[0019] Optionally, the first side is parallel to the second side, and the distance between the first side and the second side is D1.

[0020] The distance between the endpoint of the third side furthest from the first side and the first side is D2.

[0021] The ratio of D2 to D1 is 0.03 to 0.25.

[0022] Optionally, the microlens array includes a plurality of the lens groups;

[0023] In this case, at least some of the lens groups have different D2 to D1 ratios.

[0024] Optionally, the line connecting the midpoint of the first side and the midpoint of the second side is parallel to the first direction or the second direction, and the microlens array includes a plurality of the lens groups;

[0025] At least some of the lens groups are not parallel to each other in their respective first directions.

[0026] Optionally, the first directions of two adjacent lens groups are perpendicular to each other.

[0027] Optionally, the surface of the sub-lens can be concave, convex, or wavy.

[0028] Optionally, the microlens array includes a plurality of lens groups, and at least some of the lens groups have different surface shapes for their sub-lenses.

[0029] Optionally, the surface profile of the sub-lens satisfies the following expression:

[0030]

[0031] Zi = xmyn,

[0032] r2 = x2 + y2;

[0033] Where z is the sag, c is the radius of curvature, k is the conic coefficient, and r is the radius. i For a polynomial, A i Here are the polynomial coefficients, where m and n are both integers;

[0034] Different surface shapes can be obtained by adjusting at least one of the radius of curvature c, the conic coefficient k, and the polynomial coefficients.

[0035] Optionally, by setting the radius of curvature c, the conic coefficient k, and the polynomial coefficient A... i At least one of them is multiplied by a random number ε i This is used to control the changes in different surface shapes within the multiple lens groups;

[0036] in 0.9 < ε i <1.1, and ε i It follows a Gaussian distribution.

[0037] According to the microlens array of this application, the appearance of diffraction fringes caused by aperture diffraction can be effectively reduced by the close staggered arrangement; moreover, the effect of reducing diffraction fringes can be achieved by using microlenses of the same shape, which reduces the complexity of processing and is beneficial to production applications.

[0038] A second aspect of this application provides an optical system comprising the microlens array described in the first aspect above.

[0039] The lens according to this application, since it includes the aforementioned microlens array, has advantages that are substantially similar to those of a microlens array.

[0040] Optionally, the optical system includes:

[0041] light source;

[0042] Screen;

[0043] The microlens array is disposed between the light source and the screen, and the light emitted by the light source can be projected onto the screen through the microlens array to form a light field.

[0044] Optionally, the optical system further includes a camera device, with the light source located between the camera device and the microlens array, the camera device being used to capture the light field.

[0045] A third aspect of this application provides a lens comprising the microlens array described in the first aspect above.

[0046] The lens according to this application, since it includes the aforementioned microlens array, has advantages that are substantially similar to those of a microlens array.

[0047] A fourth aspect of this application provides an optical device including the lens described in the third aspect above.

[0048] The optical device according to this application, since it includes the aforementioned lens, has advantages that are substantially similar to those of a lens. Attached Figure Description

[0049] 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.

[0050] Figure 1 A three-dimensional schematic diagram of a microlens array according to a preferred embodiment of this application is shown;

[0051] Figure 2 This is a planar schematic diagram of the microlens array in Figure 1.

[0052] Figure 3 It shows Figure 2 A magnified schematic diagram of a microlens array.

[0053] Figure 4 A schematic diagram of a microlens array according to another preferred embodiment of this application is shown;

[0054] Figure 5 A schematic diagram of an optical system according to a preferred embodiment of this application is shown;

[0055] Figure 6 The diagram shows the light field effect of a typical rectangular periodically arranged microlens array projected onto a screen; and...

[0056] Figure 7 The diagram shows the light field effect of a microlens array projected onto a screen according to a preferred embodiment of this application.

[0057] Explanation of reference numerals in the attached figures:

[0058] 100: Microlens array; 101: First lens group; 102: Second lens group

[0059] 103: Third lens group; 104: Fourth lens group; 110: First row and column

[0060] 120: Second row and column; 130: Sub-lens; 131: First side

[0061] 132: Second side 133: Third side 134: Fourth side

[0062] 135: Fifth side; 136: Sixth side; L1: First direction

[0063] L2: Second direction; L3: Third direction; L4: Fourth direction

[0064] 2: Light source; 3: Screen; 4: Camera device Detailed Implementation

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] To solve the aforementioned technical problems, please refer to the appendix. Figures 1 to 4 This application provides a microlens array 100, including at least one lens group, the lens group including a plurality of sub-lenses 130 arranged sequentially, adjacent sub-lenses 130 contacting each other. In one lens group, the projection of each sub-lens 130 onto a plane parallel to the microlens array 100 has a closed shape, the closed shape having a plurality of sides, the plurality of sides including a first shape feature and a second shape feature, the first shape feature being different from the second shape feature. In one lens group, the plurality of sub-lenses 130 form a plurality of rows and columns, and the plurality of sub-lenses 130 in the rows and columns are arranged along a first direction L1 or a second direction L2, wherein the first direction L1 is opposite to the second direction L2. The plurality of rows and columns include a first row and column 110 and a second row and column 120, wherein the first row and column 110 and the second row and column 120 are arranged alternately along a third direction L3 or a fourth direction L4, wherein the third direction L3 is opposite to the fourth direction L4, and the first direction L1 is perpendicular to the third direction L3. In the first row and column 110, along the first direction L1, the first shape feature is located in front of the second shape feature. In the second row and column 120, along the first direction L1, the second shape feature is located in front of the first shape feature.

[0071] According to the microlens array of this application, the appearance of diffraction fringes caused by aperture diffraction can be effectively reduced by closely staggered arrangement; and the effect of reducing diffraction fringes can be achieved by using sub-lenses of the same shape, which reduces the complexity of processing and is beneficial to production applications.

[0072] In a lens group, each sub-lens 130 has the same shape, which facilitates template processing and production. The surface of the sub-lens 130 can be constructed as concave, convex, or wavy, etc.

[0073] In a preferred embodiment, the closed shape can be constructed as a hexagon, having a first side 131, a second side 132, a third side 133, a fourth side 134, a fifth side 135, and a sixth side 136. The first side 131 and the second side 132 are arranged opposite each other along a first direction L1 or a second direction L2. Preferably, the first side 131 and the second side 132 have the same shape and / or size. More preferably, the first side 131 and the second side 132 are parallel.

[0074] The third side 133 is connected to the first side 131, the fourth side 134 is connected to the second side 132, and the third side 133 is connected to the fourth side 134. The fifth side 135 is connected to the first side 131, the sixth side 136 is connected to the second side 132, and the fifth side 135 is connected to the sixth side 136.

[0075] The third side 133 and the fourth side 134 have different shapes and / or dimensions, and the fifth side 135 and the sixth side 136 have different shapes and / or dimensions. Preferably, the third side 133 and the fifth side 135 are axially symmetrical, that is, there is an axis of symmetry between the fifth side 135 and the third side 133 along a first direction L1 or a second direction L2. The fourth side 134 and the sixth side 136 are axially symmetrical, and there is an axis of symmetry between the sixth side 136 and the fourth side 134 along a first direction L1 or a second direction L2. The first shape feature includes the third side 133 and / or the fifth side 135, and the second shape feature includes the fourth side 134 and / or the sixth side 136.

[0076] The length of the third side 133 is less than the length of the fourth side 134. Preferably, the third side 133 is constructed as a straight side, and the fourth side 134 is constructed as a curved side. The curved side structure of the fourth side 134 is formed by the intersection of the centers of the aspherical surfaces of two adjacent sub-lenses 130 through a certain misalignment.

[0077] As shown in the figure, in a lens group, multiple sub-lenses 130 are arranged in multiple rows and columns. For example, a first row and column 110 and a second row and column 120 are arranged alternately along a second direction L2. In the first row and column 110, along the first direction L1, the third side 133 and the fifth side 135 are located in front of the fourth side 134 and the sixth side 136. In the second row and column 120, along the first direction L1, the third side 133 and the fifth side 135 are located behind the fourth side 134 and the sixth side 136. In other words, the arrangement of the sub-lenses 130 in the first row and column 110 is the opposite of that in the second row and column 120.

[0078] The distance between the first side 131 and the second side 132 is D1, and the distance between the endpoint of the third side 133 furthest from the first side 131 and the first side 131 is D2. To obtain a better "misaligned arrangement" effect, it is preferable that the ratio of D2 to D1 is 0.03 to 0.25. This can further reduce the possibility of aperture diffraction.

[0079] As one implementation, the microlens array 100 includes multiple lens groups. These lens groups can be arranged according to certain rules or randomly.

[0080] For example, at least some of the lens groups have different D2 to D1 ratios.

[0081] For example, at least some of the lens groups may have first directions L1 that are not parallel to each other. Alternatively, the first directions L1 of two adjacent lens groups may be perpendicular to each other.

[0082] For example, in Figure 4 In the illustrated embodiment, the microlens array 100 has four lens groups. The ratio of D2 to D1 in the first lens group 101 is 0.05, the ratio of D2 to D1 in the second lens group 102 is 0.25, the ratio of D2 to D1 in the third lens group 103 is 0.15, and the ratio of D2 to D1 in the fourth lens group 104 is 0.15. Furthermore, the first lens group 101 and the second lens group 102 are perpendicular to their respective first directions L1, and the first lens group 101 and the third lens group 103 are perpendicular to their respective first directions L1.

[0083] For example, at least some of the lens groups have sub-lenses 130 with different surface shapes. For instance, the surface shape of sub-lens 130 in one lens group is concave, the surface shape of sub-lens 130 in another lens group is convex, and the surface shape of sub-lens 130 in yet another lens group is wavy, etc.

[0084] Specifically, the surface profile of sub-lens 130 satisfies the following expression:

[0085]

[0086] Zi = xmyn,

[0087] r2 = x2 + y2;

[0088] Where z is the sag, c is the radius of curvature, k is the conic coefficient, and r is the radius. i For a polynomial, A i are the polynomial coefficients, where m and n are both integers.

[0089] Therefore, different surface shapes can be obtained by adjusting at least one of the radius of curvature c, the conic coefficient k, and the polynomial coefficients. For example, varying the radius of curvature between 0.99 and 1.02 will change the sag, which in turn will change the phase of the microlens.

[0090] Furthermore, by adjusting the radius of curvature c, the conic coefficient k, and the polynomial coefficient A... i At least one of them is multiplied by the random coefficient ε i This is used to control the changes in different surface shapes within multiple lens groups.

[0091] in, 0.9 < ε i <1.1, and ε i It follows a Gaussian distribution. Therefore, through the random coefficient ε i This is done by adjusting the shape of the sub-lens 130, thereby controlling the phase change of the lens and further reducing the effect of aperture diffraction.

[0092] A second aspect of this application provides an optical system including the microlens array 100 described in the first aspect. Since the lens according to this application includes the aforementioned microlens array 100, it has advantages substantially similar to those of the microlens array 100.

[0093] Figure 5 An optical system according to a preferred embodiment of this application is shown. It includes a light source 2, a screen 3, and the microlens array 100 described above.

[0094] The microlens array 100 is positioned between the light source 2 and the screen 3, allowing light emitted from the light source 2 to be projected onto the screen 3 through the microlens array 100 to form a light field. Preferably, the light source 2 is a vertical cavity laser light source 2 with a rotationally symmetric Gaussian light distribution curve and a divergence half-angle within 20°. Specifically, the light source 2 is a VCSEL light source, which consists of multiple light-emitting points.

[0095] Preferably, the optical system further includes a camera device 4, with the light source 2 located between the camera device 4 and the microlens array 100, and the camera device 4 is used to capture the light field.

[0096] For example, the optical system described above is used to photograph the light field effect of a general microlens array and the microlens array 100 in this application. The distance between the VCSEL light source and the microlens array is 0.3 mm, the distance between the microlens array and the screen 3 is 200 mm, and the camera device 4 and the light source 2 are on the same side.

[0097] Figure 6 The light field effect of a typical rectangular periodic array of microlenses projected onto a screen is shown. Figure 7 The illustration shows the light field effect projected onto a screen by a hexagonally staggered microlens array according to a preferred embodiment of this application. The periodic interval of the microlens arrangement is 55 μm, the ratio of microlens array D2 to D1 is 0.15, and in the expression, c = 1.075302998749583, k = -1.916650588415340, A20 = 0.48111, A02 = 0.71506, A40 = 0.010652, A04 = -0.040386, A22 = 0.12637.

[0098] It is obvious that Figure 6 Typical microlens arrays exhibit obvious diffraction fringes, while the hexagonally staggered microlens array of this application eliminates most of the diffraction fringes.

[0099] A third aspect of this application provides a lens comprising the microlens array 100 of the first aspect described above.

[0100] The lens according to this application, since it includes the aforementioned microlens array, has advantages that are substantially similar to those of a microlens array.

[0101] A fourth aspect of this application provides an optical device that includes the lens described in the third aspect above. For example, the optical device may be a camera, projector, mobile phone, etc.

[0102] The optical device according to this application, since it includes the aforementioned lens, has advantages that are substantially similar to those of a lens.

[0103] 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, It includes at least one lens group, the lens group comprising a plurality of sub-lenses arranged in sequence, with adjacent sub-lenses in contact with each other; In one of the lens groups, each of the sub-lenses has a closed shape in its projection onto a plane parallel to the microlens array. The closed shape has multiple sides, including a third and a fourth side connected to each other, and a fifth and a sixth side connected to each other. The third side has a different shape and / or size from the fourth side, and the fifth side has a different shape and / or size from the sixth side. The multiple sides include a first shape feature and a second shape feature. The first shape feature is different from the second shape feature. The first shape feature includes the third and the fifth side, and the second shape feature includes the fourth and the sixth side. In one of the lens groups, a plurality of the sub-lenses form a plurality of rows and columns, and the plurality of the sub-lenses in the rows and columns are arranged along a first direction or a second direction, wherein the first direction is opposite to the second direction; The plurality of rows and columns include a first row and a second row and column, wherein the first row and the second row and column are arranged alternately along a third direction or a fourth direction, wherein the third direction is opposite to the fourth direction and the first direction is perpendicular to the third direction; In the first row and column, along the first direction, the first shape feature is located in front of the second shape feature; In the second row and column, along the first direction, the second shape feature is located in front of the first shape feature.

2. The microlens array according to claim 1, characterized in that, In one of the lens groups, each of the sub-lenses has the same shape, and the closed shape has a first side and a second side disposed opposite to each other along the first direction or the second direction, the first side and the second side having the same shape and / or size.

3. The microlens array according to claim 2, characterized in that, The third side is connected to the first side, and the fourth side is connected to the second side.

4. The microlens array according to claim 3, characterized in that, The fifth side is connected to the first side, and the sixth side is connected to the second side; The first side, the second side, the third side, the fourth side, the fifth side, and the sixth side together form the closed shape.

5. The microlens array according to claim 4, characterized in that, The fifth side and the third side have an axis of symmetry arranged along the first direction or the second direction, and the sixth side and the fourth side have an axis of symmetry arranged along the first direction or the second direction.

6. The microlens array according to claim 3, characterized in that, The length of the third side is less than the length of the fourth side.

7. The microlens array according to claim 3, characterized in that, The third side is constructed as a straight side, and the fourth side is constructed as a curved side.

8. The microlens array according to claim 3, characterized in that, The first side is parallel to the second side, and the distance between the first side and the second side is D1. The perpendicular distance between the endpoint of the third side furthest from the first side and the first side is D2. The ratio of D2 to D1 is 0.03 to 0.

25.

9. The microlens array according to claim 8, characterized in that, The microlens array includes multiple lens groups; In this case, at least some of the lens groups have different D2 to D1 ratios.

10. The microlens array according to any one of claims 2-9, characterized in that, The line connecting the midpoint of the first side and the midpoint of the second side is parallel to the first direction or the second direction, and the microlens array includes a plurality of the lens groups; At least some of the lens groups are not parallel to each other in their respective first directions.

11. The microlens array according to claim 10, characterized in that, The first directions of two adjacent lens groups are perpendicular to each other.

12. The microlens array according to any one of claims 1-9, characterized in that, The surface structure of the sub-lens is concave, convex, or wavy.

13. The microlens array according to any one of claims 1-9, characterized in that, The microlens array includes multiple lens groups, and at least some of the lens groups have different surface shapes for their sub-lenses.

14. The microlens array according to claim 13, characterized in that, The surface shape of the sub-lens satisfies the following expression: ， ， ； Where z is the sag, c is the radius of curvature, k is the conic coefficient, and r is the radius. i For a polynomial, A i Here are the polynomial coefficients, where m and n are both integers; Different surface shapes can be obtained by adjusting at least one of the radius of curvature c, the conic coefficient k, and the polynomial coefficients.

15. The microlens array according to claim 14, characterized in that, By setting the radius of curvature c, the conic coefficient k, and the polynomial coefficient A... i At least one of them is multiplied by a random number ε i This is used to control the changes in different surface shapes within the multiple lens groups; in, =1, 0.9 < ε i <1.1, and ε i It follows a Gaussian distribution.

16. An optical system, characterized in that, The optical system includes a microlens array according to any one of claims 1-15.

17. The optical system according to claim 16, characterized in that, The optical system also includes: light source; Screen; The microlens array is disposed between the light source and the screen, and the light emitted by the light source can be projected onto the screen through the microlens array to form a light field.

18. The optical system according to claim 17, characterized in that, It also includes a camera device, with the light source located between the camera device and the microlens array, the camera device being used to capture the light field.

19. A lens, characterized in that, Includes the microlens array according to any one of claims 1-15.

20. An optical device, characterized in that, Includes the lens as described in claim 19.

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