Polarization integrated dodging illumination system based on micro-lens array and construction method of polarization integrated dodging illumination system

Abstract

The invention relates to the technical field of illumination, in particular to a polarization integrated dodging illumination system based on a micro-lens array and a construction method of the polarization integrated dodging illumination system. According to the invention, the micro-lenses are adopted to form the condensing micro-lens array and the projection micro-lens array, so that the system has the advantages of light, thin and compact size and the like; meanwhile, a plurality of condensing sub-lenses, a plurality of sub-masks, a polarization optical filter and a plurality of projection sub-lenses in the array form a plurality of sub-channels, polarization irradiance distribution generated on a target surface by converging sub-beams penetrating through each sub-channel is superposed, and high-uniformity polarization irradiance distribution with predefined geometrical morphology is generated; meanwhile, due to the arrangement of the polarization filter in the system, the formed polarization irradiance distribution has a unified polarization direction. Therefore, the system is suitable for accurate and steady polarization detection of targets with complex structures, diversified materials and changeable surface characteristics.

Description

Technical Field

[0001] The present invention relates to the field of lighting technology, and in particular to a polarization integrated uniform light illumination system based on a microlens array and a construction method thereof. Background Art

[0002] Active polarization detection is an important method for achieving polarization detection. It irradiates the target surface through a polarization illumination system and uses a polarization imaging system to obtain the returned light intensity and polarization information, thereby analyzing the target's surface morphology and optical material properties. During active polarization detection, the performance of the polarization illumination optical system directly determines the quality of the target's polarization characteristics. To achieve accurate and robust polarization detection of targets with complex structures, diverse materials, and variable surface properties, the illumination system must meet stringent requirements such as high irradiation uniformity, a preset geometric irradiation distribution, and a compact system structure.

[0003] In the field of active polarization detection, the active polarization detection method based on image processing under non-uniform illumination in traditional illumination systems has limited applicability. It is mainly applicable to specific conditions such as flat target shape and single material properties, and it is difficult to meet the needs of diverse scenarios. Traditional polarization illumination systems have obvious defects: (1) the irradiation area size is small when illuminating at short distances; (2) the system structure is complex and bulky, which restricts its widespread application; (3) the irradiation distribution is not uniform and it is difficult to achieve a polarization irradiance distribution with a predefined geometric shape; (4) the high stress materials in the system cause polarization state changes. Therefore, developing a high-performance polarization illumination system has become the most direct and effective solution to the existing challenges of active polarization illumination systems.

[0004] Thanks to advances in microlens array (MLA) processing technology, its commercial application has become widespread. In imaging systems, MLAs are used for integrated displays, compound-eye imaging, and light-field imaging. Their multi-microaperture characteristics and excellent beam splitting and homogenizing performance have also led to their widespread application in the lighting field. MLA-based integrated illumination polarization homogenizers offer advantages such as systematic design, strong structural flexibility, high irradiation uniformity, and a compact and lightweight design. They also require minimal light source expansion (smaller requirements for light source size and collimation). Traditional imaging beam homogenizers primarily utilize paraxial analysis, utilizing MLAs and integrated lenses to achieve beam homogenization. However, the sub-beams generated by the sub-lenses in the MLAs are difficult to perfectly focus and integrate on the projection surface. This is especially true for short-distance, high-angle polarized irradiance distributions, where excessive beam divergence can reduce irradiance uniformity. Furthermore, conventional homogenizers cannot achieve different geometric irradiance distributions by replacing MLA components (e.g., a rectangular distribution requires an MLA with rectangular sub-apertures, while a hexagonal distribution requires an MLA with hexagonal sub-apertures), limiting their flexibility. Summary of the Invention

[0005] In view of this, the present invention provides a polarization integrated homogenizing illumination system based on a microlens array and a construction method thereof, in order to solve the technical problems in the prior art of the integrated illumination polarization homogenizer based on a microlens array, such as poor focusing effect and low uniformity.

[0006] The technical solutions provided by the present invention are as follows:

[0007] In a first aspect, the present invention provides a polarization-integrated uniform light illumination system based on a microlens array, comprising: a focusing microlens array, a sub-mask array, a polarization filter, and a projection microlens array, wherein the focusing microlens array comprises a plurality of focusing sub-lenses, the sub-mask array comprises a plurality of sub-masks, each sub-mask comprises a light-transmitting area, the projection microlens array comprises a plurality of projection sub-lenses, and the plurality of focusing sub-lenses, the plurality of sub-masks, the polarization filter, and the plurality of projection sub-lenses constitute a plurality of sub-channels;

[0008] The focusing sub-lens in each sub-channel is used to discretely focus the light beam incident into the system, output a convergent sub-beam and illuminate the light-transmitting area of ​​the sub-mask of the corresponding sub-channel. The convergent sub-beam passing through the light-transmitting area in each sub-channel is projected onto the target surface after passing through the polarization filter and the projection sub-lens, forming an irradiance distribution with a preset geometric shape and a preset polarization state. The multiple irradiance distributions formed by multiple sub-channels are superimposed on the target surface to form a polarized irradiance distribution.

[0009] In an optional embodiment, the system includes at least one projection microlens array. When the projection microlens array includes multiple pieces, each sub-channel includes multiple projection sub-lenses, the sub-aperture size of the multiple projection sub-lenses in each projection microlens array is the same, the full aperture size of the multiple projection microlens arrays is the same, the sub-aperture size range is 0.5mm-3mm, the full aperture size range of each microlens array is 15mm-25mm, and the surface shape of each projection sub-lens is spherical, aspherical or free-form surface.

[0010] In an optional embodiment, the focusing microlens array includes only one focusing microlens array, and the arrangement of the focusing sub-lenses, sub-aperture size and full aperture size in the focusing microlens array are consistent with those of the projection microlens array.

[0011] In an optional embodiment, in the sub-mask array, the arrangement of the light-transmitting areas of the multiple sub-masks is the same as the arrangement of the multiple projection sub-lenses in the projection microlens array, and the light-transmitting area of ​​each sub-mask is determined by performing pre-distortion image processing on a binary image corresponding to a predefined distribution geometry.

[0012] In an optional embodiment, the focusing microlens array, sub-mask array, polarizing filter and projection microlens array are made of a resin material with a stress less than 10 nm / cm.

[0013] In an optional embodiment, when multiple projection microlens arrays are included, the polarization filter is disposed between any two projection microlens arrays.

[0014] In an optional embodiment, the sub-aperture size range of the system is 0.5 mm-3 mm, the full aperture size range of the system is 15 mm-25 mm, and the overall thickness size of the system is 10-20 mm.

[0015] In a second aspect, the present invention provides a method for constructing a polarization-integrated uniform light illumination system based on a microlens array as described in the first aspect of the present invention and any embodiment thereof, the method comprising: determining the composition and center coordinates of a projection sub-lens located at the center of the system in the projection microlens array according to projection parameters; determining the position of any projection sub-lens in the projection microlens array according to the arrangement type of the projection sub-lens and the tilt angle of the system during projection; determining the light-transmitting area of ​​each sub-mask in the sub-mask array according to ray tracing and image deformation processing of the projection microlens array; determining the parameters of a polarization filter according to polarization requirement parameters; determining the F-number of a focusing microlens array according to the F-numbers of the projection microlens array and the focusing microlens array being equal, and making the sub-aperture of the focusing microlens array equal to the sub-aperture of the projection microlens array, determining the focal length and surface parameters of the focusing microlens array, and using the projection microlens array, the sub-mask array, the polarization filter, and the focusing microlens array to form a polarization-integrated uniform light illumination system.

[0016] In an optional embodiment, the arrangement type is rectangular or hexagonal, and the position of any projection sub-lens in the projection microlens array is determined according to the arrangement type of the projection sub-lenses and the tilt angle of the system during projection, including: determining the center spacing between adjacent sub-lenses according to the sub-aperture of the projection sub-lens arrangement type; determining an offset matrix representing the offset of each projection sub-lens relative to the central projection sub-lens according to the center coordinates of the projection sub-lenses, the tilt angle of the system during projection, and the center spacing; and determining the position of any projection sub-lens in the projection microlens array according to the offset matrix.

[0017] In an optional embodiment, the light-transmitting area of ​​each sub-mask in the sub-mask array is determined based on ray tracing and image deformation processing of the projection microlens array, including: determining the field of view grid points according to a preset geometric form of the irradiance distribution; determining the size, position and distortion deformation information of the light-transmitting area of ​​the sub-mask in each sub-channel based on ray tracing of each projection sub-lens in the projection microlens array, the distortion deformation information is determined based on the ray tracing point position of the light-transmitting area of ​​the sub-mask in each sub-channel, and the ray tracing point position is determined by ray tracing within the field of view grid point; processing the distortion deformation information according to the image deformation control method of the radial basis function to determine each sub-mask in the sub-mask array.

[0018] The technical solution of the present invention has the following advantages:

[0019] The present invention employs microlenses to form a focusing microlens array and a projection microlens array, resulting in a system with advantages such as lightness, thinness, and compactness. Multiple focusing sub-lenses, multiple sub-masks, polarization filters, and multiple projection sub-lenses in the array form multiple sub-channels. The polarized irradiance distribution generated on the target surface by the convergent sub-beams of each sub-channel is superimposed, producing a highly uniform polarized irradiance distribution with a predefined geometric shape. Furthermore, the polarization filters in the system ensure that the resulting polarized irradiance distribution has a uniform polarization direction. This makes the system suitable for precise and robust polarization detection of targets with complex structures, diverse materials, and variable surface properties.

[0020] In the present invention, the light-transmitting area of ​​each sub-mask is determined by performing pre-distortion image processing on a binary image corresponding to a predefined distribution geometry. Thus, when the convergent light beam output by the focusing microlens array illuminates multiple sub-masks, the light beams passing through the light-transmitting areas of the multiple sub-masks are projected onto the target surface and the polarized irradiance distribution generated by the microlens array overlaps very accurately. As a result, the polarized irradiance distribution generated on the target surface based on this system has a very clear and sharp edge profile and a very high irradiance uniformity within the irradiance distribution.

[0021] In the present invention, low-stress materials are used to prepare each optical element in the system, ensuring that the system weight is small while ensuring accurate modulation of the system polarization state, thereby ensuring the stability of the system polarization performance to the greatest extent and reducing the influence of the optical elements on the polarization modulation effect.

[0022] In this invention, the subaperture and full-aperture sizes of the projection microlens array and the focusing microlens array can be used to determine the subaperture and full-aperture size ranges of the system. Furthermore, the overall thickness of the system can be determined based on the number of lenses used in each array. Based on this size range, it can be seen that the polarization-integrated uniform light illumination system can achieve a large irradiation area size even at short distances.

[0023] In the present invention, when multiple projection microlens arrays are provided, the polarizing filter is provided between any two projection microlens arrays, so that there is no gap between the polarizing filter and each projection microlens array, that is, close contact of the optical elements is achieved.

[0024] In the present invention, by constructing the projection microlens array, sub-mask array, polarization filter and each sub-lens and sub-mask in the focusing microlens array, the constructed polarized integrated uniform light illumination system has a high uniformity of irradiance distribution and can achieve a predefined geometric shape of polarized irradiance distribution.

[0025] In the present invention, each sub-lens in the microlens array can be effectively positioned by determining the offset matrix, thereby improving the efficiency of sub-channel analysis and alleviating the data storage burden caused by an excessive number of sub-channels. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0027] Figure 1 Schematic diagram of the structure of a polarization integrated uniform light illumination system based on a microlens array in an embodiment of the present invention;

[0028] FIG2(a), FIG2(b) and FIG2(c) are 3D disassembled optical component diagrams of a polarization-integrated uniform light illumination system based on a microlens array according to an embodiment of the present invention;

[0029] FIG3(a) and FIG3(b) are sub-mask arrays with two different predefined geometric irradiance distribution forms and polarization direction distributions in an embodiment of the present invention;

[0030] FIG4( a ) is a schematic diagram of the polygonal polarized irradiance distribution requirements according to an embodiment of the present invention;

[0031] FIG4( b ) is a 3D diagram of the irradiance simulation effect of the non-sequential ray tracing of the polarization integrated uniform light illumination system according to an embodiment of the present invention;

[0032] FIG4( c ) is a schematic diagram of the analysis results of the horizontal and vertical slices of the irradiance distribution in an embodiment of the present invention;

[0033] FIG4( d ) is a schematic diagram of polarization direction analysis of irradiance distribution on a target surface according to an embodiment of the present invention;

[0034] FIG5( a ) is a schematic diagram of polarized irradiance distribution requirements of arbitrary predefined forms in another embodiment of the present invention;

[0035] FIG5( b ) is a 3D diagram of the irradiance simulation effect of the non-sequential ray tracing of the polarization-integrated uniform light illumination system according to another embodiment of the present invention;

[0036] FIG5( c ) is a schematic diagram of the analysis results of the horizontal and vertical slices of the irradiance distribution in another embodiment of the present invention;

[0037] FIG5( d ) is a schematic diagram of polarization direction analysis of irradiance distribution on a target surface in another embodiment of the present invention;

[0038] Figure 6 Flowchart of a method for constructing a polarization-integrated uniform light illumination system based on a microlens array in an embodiment of the present invention;

[0039] Figure 7 Schematic diagram of the sampling field grid points of the geometric distribution external matrix of the custom contour in an embodiment of the present invention;

[0040] Figure 8 Schematic diagram of the positions of ray tracing points at the grid points of the field of view in an embodiment of the present invention;

[0041] Figure 9 This is a flow chart of a method for constructing a polarization-integrated uniform light illumination system based on a microlens array in another embodiment of the present invention. DETAILED DESCRIPTION

[0042] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0043] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0044] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; internal connections between two components; wireless connections or wired connections. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0045] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0046] An embodiment of the present invention provides a polarization-integrated uniform light illumination system based on a microlens array, comprising: a focusing microlens array, a sub-mask array, a polarization filter, and a projection microlens array. The focusing microlens array includes a plurality of focusing sub-lenses, the sub-mask array includes a plurality of sub-masks, and the projection microlens array includes a plurality of projection sub-lenses. The plurality of focusing sub-lenses, the plurality of sub-masks, the polarization filter, and the plurality of projection sub-lenses constitute a plurality of sub-channels.

[0047] The focusing sub-lens in each sub-channel is used to discretely focus the light beam incident into the system, output a convergent sub-beam and illuminate the sub-mask of the corresponding sub-channel. The convergent sub-beam passing through the sub-mask in each sub-channel is projected onto the target surface after passing through the polarization filter and the projection sub-lens, forming an irradiance distribution with a preset geometric shape and a preset polarization state. The multiple irradiance distributions formed by multiple sub-channels are superimposed on the target surface to form a polarized irradiance distribution with a uniformity higher than 90%.

[0048] Specifically, the system can be used as a polarization illumination system in an active polarization detection system to irradiate the target surface, providing a beam basis for obtaining the topography and optical material characteristics of the target surface. Among them, the sub-mask array and polarization filter in the system can be designed and replaced according to the geometric shape and polarization state formed on the target surface as needed, so as to meet the requirements of irradiance distribution with different predefined geometric shapes and predefined polarization states, saving the cost pressure of replacing optical elements in traditional spherical or even free-form surface systems. In addition, the polarization filter is mainly used to generate polarized light beams in the system, so it can be set at any position in the condenser microlens array and the projection microlens array, as long as the finally formed irradiance distribution has a predefined polarization state.

[0049] Among them, as Figure 1 shown, the working principle of this polarization integrated homogenizing illumination system is as follows:

[0050] The collimated beam 1 enters the polarization integrated homogenizing illumination system. First, it passes through the condenser microlens array 2 (Condenser microlens array, CMLA). The condenser microlens array 2 splits the collimated beam incident into the system into multiple converging sub-beams. The converging sub-beams illuminate the sub-mask array 3 (Sub-image array, SIA). The sub-beams passing through each sub-mask on the sub-mask array 3 are projected and imaged on the target surface 6 at a distance L from the system after passing through each sub-channel of the projection microlens array 5 (Projection microlens array, PMLA). Since there is also a polarization filter 4 between the sub-mask array 3 and the projection microlens array 5 in the system, the finally formed irradiance distribution on the target surface 6 has a polarization state, so it can be called an irradiance distribution 7 with a polarization state. The range of the projection distance L can be set according to actual needs, and the range of the projection distance L is 100mm < L < 5000mm. Among them, each projection sub-channel has the same focal length f, and the aperture of each sub-channel is p.

[0051] Based on multiple condenser sub-lenses, multiple sub-masks, and multiple projection sub-lenses, this polarization integrated homogenizing illumination system can be regarded as composed of multiple discretely arranged sub-channel optical systems. Among them, each sub-channel optical system includes a condenser sub-lens 2A, a sub-mask 3A, a polarization filter 4A, and a projection sub-lens 5A. From the above condenser sub-lens 2A, sub-mask 3A, polarization filter 4A, and projection sub-lens 5A, an integrated projection sub-channel based on the Kohler illumination system can be formed. And the polarization integrated homogenizing illumination system integrating the condenser microlens array, sub-mask array, polarization filter, and projection microlens array can be called a Kohler illumination integrated projection system.

[0052] In this polarization-integrated uniform illumination system, each converging sub-beam, after passing through the projection sub-lens of its corresponding sub-channel, forms a polarized irradiance distribution on the target surface 6. Each integrated projection sub-channel can independently generate a polarized irradiance distribution on the target surface 6. Ultimately, the polarized irradiance distributions generated by all integrated projection sub-channels on the target surface 6 are superimposed to produce a highly uniform polarized irradiance distribution with a predefined geometric shape and a uniform polarization direction.

[0053] The present invention employs microlenses to form a focusing microlens array and a projection microlens array, resulting in a system with advantages such as lightness, thinness, and compactness. Multiple focusing sub-lenses, multiple sub-masks, polarization filters, and multiple projection sub-lenses in the array form multiple sub-channels. The polarized irradiance distribution generated on the target surface by the convergent sub-beams of each sub-channel is superimposed, producing a highly uniform polarized irradiance distribution with a predefined geometric shape. Furthermore, the polarization filters in the system ensure that the resulting polarized irradiance distribution has a uniform polarization direction. This makes the system suitable for precise and robust polarization detection of targets with complex structures, diverse materials, and variable surface properties.

[0054] In an optional embodiment, the projection microlens array includes at least one projection microlens array. When the projection microlens array includes multiple projection microlenses, each sub-channel includes multiple projection sub-lenses. The sub-aperture size of the multiple projection sub-lenses in each projection microlens array is the same, and the full aperture size of the multiple projection microlens arrays is the same, with the sub-aperture size ranging from 0.5 mm to 3 mm. The full aperture size of each microlens array ranges from 15 mm to 25 mm. The surface shape of each projection sub-lens is spherical, aspherical, or free-form. By using aspherical or free-form surfaces, the number of projection sub-lenses in the sub-channel can be reduced, and the thickness of the projection microlens array in the light transmission direction can be reduced. When multiple projection microlens arrays are included, a polarization filter is provided between any two projection microlens arrays.

[0055] Specifically, the system may include one or more projection microlens arrays. When multiple projection microlens arrays are included, each subchannel includes multiple projection sub-lenses in the light transmission direction, that is, each subchannel includes a projection sub-lens group. Furthermore, when multiple projection microlens arrays are provided, the multiple projection microlens arrays are preferably closely attached (with minimal gaps between them), and a polarizing filter is provided between any two projection microlens arrays.

[0056] In each projection microlens array, the sub-aperture size of the multiple projection sub-lenses is the same. In this embodiment, the sub-aperture size range is set to 0.5 mm-3 mm. At the same time, when the projection microlens array includes multiple microlens arrays, the full aperture size of the multiple microlens arrays is the same. In this embodiment, the full aperture size range is set to 15 mm-25 mm.

[0057] In an optional embodiment, the focusing microlens array includes a focusing microlens array, the arrangement, sub-aperture size, and full-aperture size of the focusing sub-lenses in the focusing microlens array are consistent with those of the projection microlens array, and the F-number of the focusing sub-lenses is equal to the F-number of the projection sub-lens group. Specifically, the sub-aperture size of each focusing sub-lens in the focusing microlens array is the same as the sub-aperture size of the projection sub-lens in the corresponding sub-channel, the arrangement of the focusing sub-lenses in the focusing microlens array is the same as the arrangement of the projection sub-lenses in the projection microlens array, and the full-aperture size of the focusing microlens array and the projection microlens array is the same, for example, the sub-aperture size range of the focusing microlens array is 0.5 mm-3 mm, and the full-aperture size range is 15 mm-25 mm.

[0058] In an optional embodiment, there is only one focusing micro-lens array, which only performs the function of light beam convergence and can be made of spherical sub-lenses.

[0059] In an optional embodiment, the sub-mask array includes a plurality of sub-masks, each sub-mask includes a light-transmitting area, and the arrangement of the light-transmitting areas of the plurality of sub-masks in the sub-mask array is the same as the arrangement of the plurality of projection sub-lenses in the projection microlens array, and the light-transmitting area of ​​each sub-mask is determined by performing pre-distortion image processing on a binary image corresponding to a predefined distribution geometry. Specifically, since the projection imaging of the optical sub-channel often contains complex optical distortions, such as trapezoidal distortion and barrel distortion, the shape of the light-transmitting area of ​​each sub-mask in the sub-mask array can be obtained by performing pre-distortion image processing on a binary image corresponding to a predefined distribution geometry. Specifically, the pre-distortion method for the sub-mask adopts an image deformation control method of a radial basis function.

[0060] Therefore, through the above-mentioned design of the light-passing area of ​​each sub-mask in the sub-mask array, when the multiple converging sub-beams output by the focusing microlens array are irradiated on multiple sub-masks, the light beams passing through the light-passing areas of the multiple sub-masks are projected on the target surface by the microlens array. The polarized irradiance distribution generated on the target surface by the microlens array is very accurately overlapped. Therefore, the polarized irradiance distribution generated on the target surface based on this system has a very clear and sharp edge profile and a very high irradiance uniformity within the irradiance distribution. Specifically, an irradiance distribution with a uniformity higher than 90% and a very sharp edge irradiance cutoff can be generated on the target surface. Through the personalized design of each light-passing area in the sub-mask array, a polarized irradiance distribution of any shape can be formed on the target surface.

[0061] In an optional embodiment, the focusing microlens array, sub-mask array, polarization filter and projection microlens array are made of a resin material with a stress of less than 10nm / cm. Specifically, stress will cause a birefringence effect inside the material, that is, the refractive index of the material in different directions changes. This anisotropy will change the polarization state of the incident light (such as linear polarization becomes elliptical polarization, or introduce phase delay), thereby affecting the performance of the optical system. Based on this, each optical element in the system is made of a low-stress material, that is, the stress of the material of each optical element is less than 10nm / cm, where nm / cm represents the optical path difference per unit length, and this unit is used to represent stress in this embodiment. By using low-stress materials to prepare each optical element in the system, the precise modulation of the polarization state of the system is guaranteed while ensuring a small system weight, thereby ensuring the stability of the system polarization performance to the greatest extent possible and reducing the influence of the optical elements on the polarization modulation effect.

[0062] In an optional embodiment, the subaperture size range of the system is 0.5mm-3mm, the full aperture size range of the system is 15mm-25mm, and the overall thickness of the system is 10-20mm. Specifically, based on the subaperture size and full aperture size of the projection microlens array and the focusing microlens array, the subaperture size range and full aperture size range of the system can be determined; the overall thickness of the system can also be determined based on the number of lenses used in each array. Based on the size range of the system, it can be seen that the polarization-integrated uniform light illumination system of this embodiment can achieve a large irradiation area size when illuminating at a short distance.

[0063] As a specific application embodiment of the present invention, as shown in Figures 2(a), 2(b) and 2(c), there are 3D disassembled optical element diagrams of a polarized integrated uniform light illumination system, including a focusing microlens array 2, a sub-mask array 3, a polarizing filter 4 and a projection microlens array. The projection microlens array includes three pieces, namely a first projection microlens array 51, a second projection microlens array 52, and a third projection microlens array 53. The polarizing filter 4 is preferably arranged between the two non-convex surfaces of the first projection microlens array 51 and the second projection microlens array 52. ​​In this system, the optical elements are closely connected together, with a compact optical structure. The surface shape of each projection sub-lens in the projection microlens array is a free-form surface, which greatly improves the integrated projection quality of the system. At the same time, the stacked structure of the three projection microlens arrays further eliminates spherical aberration and field curvature, allowing the sub-channels to have larger sub-apertures, thereby improving the maximum resolution that the system can achieve.

[0064] The system utilizes a three-piece, polarization-integrated uniform illumination system based on a stacked free-form surface projection microlens array, enabling high resolution. Consequently, the polarized irradiance distribution generated on the target surface has a sharp, clean contour. Furthermore, all optical components in the system are constructed of low-stress materials, eliminating the influence of the individual optical components on the polarization orientation of the polarized irradiance distribution generated on the target surface.

[0065] In addition, in this polarization-integrated uniform light illumination system, predefined polarized irradiance distributions of different shapes and polarization directions can be achieved by simply replacing different sub-mask arrays 3 and polarization filters 4. Figures 3(a) and 3(b) show two sub-mask arrays corresponding to irradiance distributions of different shapes. Figure 3(a) is a sub-mask array corresponding to a polygonal polarized irradiance distribution, which includes a plurality of octagonal light-transmitting areas. Figure 3(b) corresponds to another sub-mask array of polarized irradiance distribution of any predefined shape, which includes a plurality of light-transmitting areas of predefined shapes.

[0066] Based on the polarization-integrated projection illumination homogenization system of this embodiment, the sub-mask array shown in Figure 3(a) is employed in accordance with the polygonal polarized irradiance distribution requirements shown in Figure 4(a). Figure 4(b) shows a 3D simulation of the irradiance effect of the polarization-integrated homogenization illumination system using non-sequential ray tracing. The specific irradiance distribution is shown in Figure 4(c), along with the results of horizontal and vertical slice analysis. Figure 4(d) further provides a polarization direction analysis of the irradiance distribution on the target surface. The results shown in Figure 4(c) demonstrate that the system achieves high irradiance uniformity exceeding 90%. Furthermore, the irradiance distribution exhibits a polygonal geometry with clear, sharp edges. The results shown in Figure 4(d) demonstrate that the entire irradiance distribution has a uniform polarization direction (90 degrees from vertical), demonstrating the system's ability to manipulate the polarization state of the beam. Furthermore, the resulting polarized irradiance distribution does not produce distributions with other polarization directions, demonstrating the system's high polarization control stability.

[0067] Based on the polarization-integrated projection illumination homogenization system of this embodiment, the sub-mask array shown in Figure 3(b) is employed, according to the requirements for the polarization irradiance distribution of any predefined shape as shown in Figure 5(a). Figure 5(b) shows a 3D simulation of the irradiance effect of the polarization-integrated homogenization illumination system using non-sequential ray tracing. The specific irradiance distribution is shown in Figure 5(c), along with the results of the horizontal and vertical slice analysis. Figure 5(d) further provides the polarization direction analysis of the irradiance distribution on the target surface. The results shown in Figure 5(c) demonstrate that the system achieves high irradiance uniformity exceeding 90%. Furthermore, the irradiance distribution exhibits a predefined geometric shape with clear, sharp edges. The results shown in Figure 5(d) demonstrate that the entire irradiance distribution has a uniform polarization direction (-45 degrees from vertical), demonstrating the system's ability to manipulate the polarization state of the beam. Furthermore, the generated polarization irradiance distribution does not produce distributions with other polarization directions, demonstrating the system's high polarization control stability.

[0068] The embodiment of the present invention also provides a method for constructing the polarization integrated uniform light illumination system based on the microlens array described in the above embodiment, such as Figure 6 As shown, the method includes:

[0069] Step S101 determines the composition and center coordinates of the projection sub-lens located at the center of the projection micro-lens array based on projection parameters. Specifically, the composition of the projection sub-lens group in the projection micro-lens array is determined based on the desired irradiance distribution and projection distance. The projection micro-lens array is composed of multiple projection sub-lenses. Therefore, when designing the projection micro-lens array, it is necessary to determine the position of each projection sub-lens while also meeting the requirements for compactness and thinness of the projection micro-lens array. When determining the position of the projection sub-lenses, the position of one of the projection sub-lenses is first determined, such as the projection sub-lens located at the center of the system or at the center of the projection micro-lens array. The position of each projection sub-lens is then determined by expanding outward.

[0070] Specifically, in order to determine the position, this embodiment first determines a coordinate system in the system, and then determines the position of the projection sub-lens located at the center of the system according to the required projection target size S and projection distance L and other projection parameters. In this embodiment, the position coordinate is defined as (i central ,j central In addition, the material of the projection sub-lens can be determined based on the low stress requirement, and the surface shape of the projection sub-lens can be optimized by constraining optical parameters such as focal length and image height. When optimizing the surface shape, it is necessary to ensure the imaging quality of the projection sub-lens while ensuring that there is no excessive loss of light, while also meeting the requirements of making the overall projection sub-lens group compact and lightweight.

[0071] Step S102, determining the position of any projection sub-lens in the projection micro-lens array according to the arrangement type of the projection sub-lenses and the tilt angle of the system during projection; wherein, the arrangement type specifically refers to the shape of the projection sub-lenses arranged in the projection micro-lens array. When the shapes of the projection sub-lenses are different, the calculation method for determining the position of other projection sub-lenses is also different. At the same time, it is also necessary to consider the tilt angle of the system during projection to determine the spatial offset of each projection sub-lens. Finally, the position of each projection sub-lens is calculated according to the arrangement type and tilt angle, and based on this position, the position of (i central ,j central ) position is offset to obtain a projection microlens array.

[0072] Step S103, determining the light-transmitting area of ​​each sub-mask in the sub-mask array based on ray tracing and image deformation processing of the projection microlens array; specifically, because the image formed by each sub-channel is projected onto the target surface through the projection microlens array in the sub-channel, the relevant information of the light-transmitting area of ​​the sub-mask in each projection sub-channel can be determined based on the projection microlens array by ray tracing; in addition, when determining the light-transmitting area of ​​each sub-mask in the sub-mask array, since the projection imaging of the optical sub-channel often contains complex optical distortions, such as trapezoidal distortion and barrel distortion, it is necessary to further perform pre-distortion image processing on the binary image corresponding to the predefined distribution geometry, such as image deformation processing, so as to obtain the light-transmitting area of ​​the sub-mask in each sub-channel.

[0073] Step S104, determining the parameters of the polarization filter according to the polarization requirement parameters; specifically, in this embodiment, the irradiance distribution generated on the target surface needs to have a predefined polarization state, so the type of polarization filter and other parameters can be selected according to the required polarization state.

[0074] Step S105, based on the aperture and focal length of the projection sub-lens, the F number of the projection sub-lens (the ratio of the focal length of the projection sub-lens to the sub-aperture) can be determined; further, the F number of the projection microlens array is made equal to the F number of the focusing microlens array, and the focal length and surface parameters of the focusing microlens array are determined in combination with the sub-aperture of the focusing microlens array. A polarization integrated uniform light illumination system is constructed using a projection microlens array, a sub-mask array, a polarization filter, and a focusing microlens array. Specifically, the focusing sub-lens can be obtained by splicing plano-convex spherical sub-lenses. At the same time, in order to obtain the maximum light efficiency in the system, the F number of the focusing microlens array and the projection microlens array are set to be the same. In the system, there is only one focusing microlens array, which only performs the function of light beam convergence. A spherical sub-lens can be used, and the specific curvature radius can be calculated based on the F number and sub-aperture.

[0075] In an optional embodiment, determining the position of any projection sub-lens in the projection micro-lens array according to the arrangement type of the projection sub-lenses and the tilt angle of the system during projection includes:

[0076] Step S201, determine the center spacing of adjacent sub-lenses based on the sub-aperture of the projection sub-lens arrangement type; specifically, when the arrangement type of the projection sub-lenses is different, the center spacing of adjacent sub-lenses is different. Therefore, when determining the center spacing, it is necessary to first determine the arrangement type. Among them, when the arrangement type is a rectangular arrangement, the center spacing of adjacent sub-lenses is the sub-aperture size of the projection sub-lens; when the arrangement type is a hexagonal arrangement, if the sub-aperture size of the projection sub-lens is p, then the spacing of the sub-lenses in the y direction is The pitch of the sub-lenses in the x direction is Δx=3p / 2.

[0077] Step S202: determining an offset matrix representing the offset of each projection sub-lens relative to the central projection sub-lens based on the center coordinates of the projection sub-lens, the tilt angle of the system during projection, and the center spacing; wherein the offset matrix is ​​a data matrix consisting of the XY coordinate position of each sub-channel in the polarization-integrated uniform light illumination system.

[0078] Specifically, when the arrangement type is a rectangular arrangement, the offset matrix is ​​expressed using the following formula:

[0079]

[0080] Where XDE(i,j), YDE(i,j), and ZDE(i,j) are the offsets of the projection sub-lens in the projection microlens array relative to the optimized central projection sub-lens in the x, y, and z directions, respectively. x and p y is the center distance between adjacent projection sub-lenses in the rectangular arrangement projection micro-lens array, and p is the aperture size of the projection sub-lens. When considering a dense arrangement, that is, p x =p y =p, θ represents the tilt angle of the system during projection.

[0081] Specifically, when the arrangement type is a hexagonal arrangement, it is decomposed into two different matrix arrangements, that is, the odd-numbered columns of the arrangement are regarded as a rectangular arrangement, and the even-numbered columns of the arrangement are regarded as a rectangular arrangement. Therefore, two offset matrices M1 and M2 are determined for the two rectangular arrangements. The two offset matrices are respectively expressed by the following formulas:

[0082]

[0083]

[0084] Where XDE1(i, j), YDE1(i, j), and ZDE1(i, j) are the offsets of the projection sub-lens in the projection microlens array relative to the optimized central projection sub-lens in the x, y, and z directions, respectively.

[0085] Step S203 determines the position of any projection sub-lens in the projection microlens array based on the offset matrix. Specifically, after determining the offset matrix, the central projection sub-lens can be conveniently moved to any sub-lens position in the projection microlens array. By offsetting the sub-channels in the offset matrix, each sub-lens in the microlens array can be effectively positioned. Addressing (i.e., determining the sub-lens position) using the determined offset matrix improves the efficiency of sub-channel analysis and reduces the data storage burden caused by an excessive number of sub-channels.

[0086] In an optional embodiment, determining the light-transmitting area of ​​each sub-mask in the sub-mask array based on ray tracing and image deformation processing of the projection microlens array includes:

[0087] Step S301, determining the field of view grid points according to the preset geometric form of the irradiance distribution; specifically, Figure 7 As shown, according to the design requirements, the irradiance distribution 7 generated on the target surface needs to have a preset geometric shape, which can be understood as a geometric distribution of a custom profile. After the preset geometric shape is determined, the matrix area circumscribed by it (geometric distribution) is uniformly sampled to form the field of view grid points 8.

[0088] Step S302, determining the size, position, and distortion information of the light-transmitting area of ​​the sub-mask in each sub-channel by ray tracing each projection sub-lens in the projection microlens array, wherein the distortion information is determined based on the ray tracing point position of the convergent sub-beam in each sub-channel, and the ray tracing point position is determined by ray tracing the field of view grid points; specifically, Figure 8 As shown, by tracing rays through the subchannels of the projection microlens array, ray tracing point positions 10 corresponding to the field of view grid points where the light-clearance areas of the submasks within the subchannels are located can be obtained, where grid point 9 corresponds to the ideal grid position of the ideal sub-image. By performing the above ray tracing analysis on each subchannel, ray tracing point positions 10 corresponding to the light-clearance areas of the submasks within each subchannel can be obtained. Based on this information, the size, position, and distortion information of the light-clearance areas of each submask can be determined.

[0089] Step S303: Process the distortion information using a radial basis function image deformation control method to determine the clear area of ​​each sub-mask in the sub-mask array. Specifically, the acquired distortion information can be further processed using a radial basis function image deformation method to offset the distortion, thereby determining the clear area of ​​each sub-mask in the sub-mask array.

[0090] As a specific application example of the embodiment of the present invention, Figure 9 As shown, the method for constructing a polarization integrated uniform light illumination system based on a microlens array is specifically implemented using the following process:

[0091] (a) First, we need to carry out step S1, which is the optimization design of the projection sub-lens group. Figure 1As shown in FIG, according to the required projection target size S and projection distance L, the projection sub-lens group can be composed of 1-3 optical lenses, and the lens materials are all set to low stress materials (<10nm / cm). The lens surface shape is optimized by constraining optical parameters such as focal length and image height. Specifically, in the optimization design, it is necessary to ensure the imaging quality of the projection sub-lens group, while ensuring that there is no excessive loss of light, and at the same time, satisfying the overall compactness and lightness of the projection sub-lens group. The projection sub-lens group obtained by step S1 is defined as the lens sub-lens group at the center coordinate position of the system, that is, the lens sub-lens group located at (i central ,j central ).

[0092] (b) Then proceed to step S2, which calculates the offset matrix of the subchannels in the polarization-integrated uniform illumination system based on a microlens array. The offset matrix is ​​a data matrix consisting of the XY coordinate positions of each subchannel in the polarization-integrated uniform illumination system. Its composition is determined by the sub-aperture size p of the subchannel and the arrangement distance between the subchannels. When the MLA array arrangement type is rectangular, the offset matrix is ​​generated based on the required MLA sub-lens arrangement type and the tilt angle θ of the system during integrated projection:

[0093]

[0094] p x and p y is the center distance between adjacent lenses in a rectangular arrangement of microlens array, and p is the aperture size of the sub-lens. When considering a dense arrangement, that is, p x =p y =p.

[0095] For the regular hexagonal sub-lens arrangement, it can be decomposed into two different rectangular arrangements, corresponding to the offset matrices M1 and M2 respectively. The sub-aperture size of the sub-lens is p, and the spacing of the sub-lenses in the y direction is The spacing between the sub-lenses in the x direction is Δx = 3p / 2. If ML(i center ,j center ) is the projection sub-lens group located at the center of the system after optimization in step S1. To achieve tilted projection, it can have a tilt angle θ. M1(i, j) and M2(i, j) are the offsets of the central sub-lens respectively. The sub-lens position can be obtained by matrices M1 and M2:

[0096]

[0097]

[0098] Among them, XDE1(i,j), YDE1(i,j), and ZDE1(i,j) are the offsets of the sub-lenses in the microlens array relative to the optimized central sub-lens in the x, y, and z directions, respectively.

[0099] (c) Sub-channel offset addressing step S3. Through the above-mentioned microlens array offset matrix, the optimized central sub-lens can be easily moved to any sub-lens position in the microlens array. By offsetting the sub-channels in the offset matrix, each sub-lens in the microlens array can be effectively positioned. The offset matrix and addressing method can improve the efficiency of sub-channel analysis and reduce the data storage burden caused by the excessive number of sub-channels. The offset matrix is ​​used in ray tracing to determine the common area, and the offset matrix can also be used to trace the main light, and then the light-transmitting area of ​​the sub-mask is generated by the image pre-distortion method.

[0100] (d) Subchannel distortion analysis S4. By performing ray tracing analysis on the integrated projection subchannel optical system, the size, position, and even distortion information of the light-transmitting area in each projection subchannel can be obtained. Figure 7 As shown, on the target surface 6, the predefined polarized irradiance distribution 7 is a geometric distribution with a custom profile. By sampling the field of view grid points 8 in its circumscribed rectangular area and further performing ray tracing on the sub-channels in the integrated projection polarization system, the following can be obtained: Figure 8 The ray tracing point positions 10 are shown for the field of view grid points corresponding to the clear areas within the sub-channels, where grid point 9 corresponds to the ideal grid position for the clear areas of the ideal sub-mask. Performing the above ray tracing analysis on each sub-channel yields the ray tracing point positions 10 corresponding to the clear areas of the sub-mask within each sub-channel.

[0101] (e) RBF image pre-distortion step S5. The size, position, and distortion information of the light-transmitting area of ​​the sub-mask in each projection sub-channel obtained in step S4 (the ray tracing point position 10 of the light-transmitting area of ​​the sub-mask in each sub-channel) are further combined with the RBF image deformation control method to obtain the light-transmitting area of ​​each sub-mask in the polarization-integrated uniform illumination system.

[0102] (f) Step S6 of constructing a polarized uniform illumination system. The focusing sub-lens can be constructed by splicing plano-convex spherical sub-lenses. To maximize the system's optical efficiency, its optical F / # should be the same as that of the projection sub-lens group. Based on the projection sub-lens group obtained in step S1, the focusing sub-lens, and the light-transmitting area of ​​the sub-mask obtained in step S5, a complete polarized integrated uniform illumination system based on a microlens array can be obtained.

[0103] Although exemplary embodiments and their advantages have been described in detail, those skilled in the art may make various changes, substitutions, and modifications to these embodiments without departing from the spirit of the present invention and the scope of protection defined by the appended claims. Such modifications and variations fall within the scope defined by the appended claims. For other examples, those skilled in the art will readily appreciate that the order of the process steps may be varied while remaining within the scope of protection of the present invention.

[0104] Furthermore, the scope of application of the present invention is not limited to the processes, mechanisms, manufactures, compositions of matter, means, methods, and steps of the specific embodiments described in the specification. From the disclosure of the present invention, a person of ordinary skill in the art will readily understand that any currently existing or later developed processes, mechanisms, manufactures, compositions of matter, means, methods, or steps that perform substantially the same functions or achieve substantially the same results as the corresponding embodiments described herein may be applied in accordance with the present invention. Therefore, the claims appended hereto are intended to include within their scope such processes, mechanisms, manufactures, compositions of matter, means, methods, or steps.

Claims

1. A polarization integrated uniform light illumination system based on a microlens array, characterized in that: include: A focusing microlens array, a sub-mask array, a polarizing filter, and a projection microlens array, wherein the focusing microlens array includes a plurality of focusing sub-lenses, the sub-mask array includes a plurality of sub-masks, each sub-mask includes a light-transmitting area, and the projection microlens array includes a plurality of projection sub-lenses. The plurality of focusing sub-lenses, the plurality of sub-masks, the polarizing filter, and the plurality of projection sub-lenses constitute a plurality of sub-channels; The focusing sub-lens in each sub-channel is used to discretely focus the light beam incident into the system, output a convergent sub-beam and illuminate the light-transmitting area of ​​the sub-mask of the corresponding sub-channel. The convergent sub-beam passing through the light-transmitting area in each sub-channel is projected onto the target surface after passing through the polarization filter and the projection sub-lens, forming an irradiance distribution with a preset geometric shape and a preset polarization state. The multiple irradiance distributions formed by multiple sub-channels are superimposed on the target surface to form a polarized irradiance distribution.

2. The polarization integrated uniform light illumination system based on microlens array according to claim 1, characterized in that: The system includes at least one projection microlens array. When the projection microlens array includes multiple elements, each sub-channel includes multiple projection sub-lenses. The sub-aperture sizes of the multiple projection sub-lenses in each projection microlens array are the same. The full aperture sizes of the multiple projection microlens arrays are the same, with the sub-aperture sizes ranging from 0.5 mm to 3 mm. The full aperture size of each microlens array ranges from 15 mm to 25 mm. The surface shape of each projection sub-lens is spherical, aspherical, or free-form.

3. The polarization integrated uniform light illumination system based on microlens array according to claim 2, characterized in that: The light-collecting micro-lens array comprises only one light-collecting micro-lens array, and the arrangement of the light-collecting sub-lenses, the sub-aperture size and the full aperture size in the light-collecting micro-lens array are consistent with those of the projection micro-lens array.

4. The polarization integrated uniform light illumination system based on microlens array according to claim 1, characterized in that: In the sub-mask array, the arrangement of the light-transmitting areas of the multiple sub-masks is the same as the arrangement of the multiple projection sub-lenses in the projection microlens array, and the light-transmitting area of ​​each sub-mask is determined by performing pre-distortion image processing on a binary image corresponding to a predefined distribution geometric form.

5. The polarization integrated uniform light illumination system based on microlens array according to claim 1, characterized in that: The light-collecting microlens array, sub-mask array, polarizing filter and projection microlens array are made of resin material with a stress less than 10 nm / cm.

6. The polarization integrated uniform light illumination system based on microlens array according to claim 2, characterized in that: When a plurality of projection microlens arrays are included, the polarization filter is arranged between any two projection microlens arrays.

7. The polarization integrated uniform light illumination system based on microlens array according to claim 1, characterized in that: The sub-aperture size range of the system is 0.5mm-3mm, the full aperture size range of the system is 15mm-25mm, and the overall thickness size of the system is 10-20mm.

8. A method for constructing the polarization-integrated uniform light illumination system based on a microlens array according to any one of claims 1 to 7, characterized in that: The method comprises: Determine the composition and center coordinates of the projection sub-lens located at the center of the system in the projection micro-lens array according to the projection parameters; Determining the position of any projection sub-lens in the projection micro-lens array according to the arrangement type of the projection sub-lenses and the tilt angle of the system during projection; Determining the light-transmitting area of ​​each sub-mask in the sub-mask array based on ray tracing of the projection microlens array and image deformation processing; Determine the parameters of the polarization filter according to the polarization requirement parameters; The F-number of the condensing microlens array is determined based on the F-numbers of the projection microlens array and the condensing microlens array being equal, and the subaperture of the condensing microlens array is made equal to the subaperture of the projection microlens array, and the focal length and surface parameters of the condensing microlens array are determined. The projection microlens array, the submask array, the polarization filter and the condensing microlens array are used to form a polarization integrated uniform light illumination system.

9. The method according to claim 8, characterized in that The arrangement type is rectangular or hexagonal, and the position of any projection sub-lens in the projection micro-lens array is determined according to the arrangement type of the projection sub-lens and the tilt angle of the system during projection, including: Determine the center distance between adjacent sub-lenses according to the sub-aperture of the projection sub-lens arrangement type; Determine an offset matrix representing the offset of each projection sub-lens relative to the central projection sub-lens according to the center coordinates of the projection sub-lens, the tilt angle of the system during projection, and the center distance; The position of any projection sub-lens in the projection microlens array is determined according to the offset matrix.

10. The method according to claim 8, characterized in that The light-transmitting area of ​​each sub-mask in the sub-mask array is determined based on ray tracing of the projection microlens array and image deformation processing, including: Determine the field of view grid points based on the preset geometric shape of the irradiance distribution; Determining the size, position, and distortion information of the light-clearance area of ​​the sub-mask in each sub-channel by ray tracing each projection sub-lens in the projection microlens array, wherein the distortion information is determined based on the positions of ray tracing points in the light-clearance area of ​​the sub-mask in each sub-channel, the ray tracing point positions being determined by ray tracing within a grid point of the field of view; The distortion information is processed according to an image deformation control method of a radial basis function to determine each sub-mask in the sub-mask array.

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