Microstructural Patterns for Suppressing Moiré Patterns in Privacy Films, Their Generation Methods, and Applications

Abstract

This invention relates to the field of optical privacy film technology, specifically to a privacy film microstructure pattern for suppressing moiré patterns, its generation method, and its application. The method involves generating a basic dot matrix within a design area. This basic dot matrix is ​​arranged in a two-dimensional pattern along the x and y directions with a basic spacing. A random perturbation is applied to each point in the basic dot matrix, causing each point to deviate from its original grid position, with the spacing between adjacent points remaining within a preset range after the perturbation. Using the perturbed point set as seed points, an irregular polygonal mesh structure is generated. The mesh lines in the irregular polygonal mesh structure are extracted as the microstructure lines of the privacy film. These microstructure lines are then solidified into polygonal lines with a predetermined line width, forming the privacy film microstructure pattern. This privacy film microstructure pattern for suppressing moiré patterns possesses privacy protection, moiré pattern suppression, and a flexible design and generation method.

Description

Technical Field

[0001] This invention relates to the field of optical privacy film technology, specifically to a privacy film microstructure pattern for suppressing moiré patterns, its generation method, and its application. Background Technology

[0002] With the widespread use of electronic information terminals, privacy films, as an important material for protecting privacy and improving visual security, are widely used in mobile terminals, tablets, laptops, and public displays. Traditional privacy films mainly adopt regular periodic structures, such as micron-level gratings, aperture arrays, stripe structures, microlens arrays, and etched textures, to limit the viewing angle by directional control of incident light.

[0003] However, traditional regular periodic structures face two main problems in practical applications: First, when a regular periodic structure forms a composite periodic structure with a display pixel array or other periodic layers, moiré patterns are easily generated. Moiré patterns are low-frequency artifacts formed by the interference and superposition of two or more periodic structures in spatial frequency, direction, or phase. They manifest as stripes, ripples, meshes, and other artifacts in the observed image, severely affecting visual quality and user experience.

[0004] Second, regular periodic structures place high demands on machining accuracy, directional control, and parameter consistency during actual manufacturing. If the structural design deviates from expectations or couples with the outer protective film, local performance fluctuations are likely to occur, further exacerbating the moiré effect.

[0005] In privacy screen protector systems, moiré patterns are easily formed when regular periodic structures are superimposed on the display pixel array, the texture of the outer protective film, and the grating structure of the observation instrument. Therefore, a single regular periodic structure has high sensitivity to moiré patterns in practical applications. Summary of the Invention

[0006] To address the shortcomings of the existing technology, this invention designs a privacy screen protector microstructure pattern for suppressing moiré patterns and provides a method for generating the privacy screen protector microstructure pattern for suppressing moiré patterns. This method is based on a two-dimensional dot matrix with a basic spacing. By perturbing, the actual dot spacing is distributed within a preset range, thereby constructing an irregular polygonal grid structure with complex spectral characteristics. The originally discrete frequency spectral lines will be expanded and distributed within the corresponding frequency domain interval, so that the spectral energy is no longer concentrated at a single frequency point. Theoretically, this can reduce the possibility of coupling with display pixels or other periodic structures. This makes the privacy screen protector microstructure pattern usable for making privacy screen protectors for mobile phones, tablets, laptops, automotive displays, or public displays.

[0007] The objective of this invention is achieved as follows: A method for generating a privacy screen microstructure pattern to suppress moiré patterns includes the following steps: Step S1: Generate a basic dot matrix in a region to be designed. The basic dot matrix is ​​arranged in two dimensions in the x and y directions and has a basic spacing. Step S2: Apply a random perturbation to the position of each point in the basic dot matrix, so that each point deviates from the original grid position, and the distance between two adjacent points after the perturbation is within a preset range; Step S3: Using the perturbed point set as seed points, generate an irregular polygonal mesh structure; Step S4: Extract the grid lines from the irregular polygonal grid structure as the microstructure lines of the privacy film; Step S5: Solidify the microstructure lines into polygonal lines according to a predetermined line width to form a privacy film microstructure pattern.

[0008] In the above-mentioned method for generating a privacy film microstructure pattern to suppress moiré patterns, the basic spacing in step S1 is 10 micrometers.

[0009] In the above-mentioned method for generating microstructure patterns of privacy films to suppress moiré patterns, in step S2, the amplitude of the random disturbance is ±2.5 micrometers, the random disturbance is generated independently in the x and y directions respectively, the disturbance distribution function is any one of uniform distribution, normal distribution or mixed distribution, and the preset range is 7 micrometers to 12 micrometers.

[0010] The above-mentioned method for generating microstructure patterns for privacy films to suppress moiré patterns includes, in step S3, generating an irregular polygonal mesh structure through a spatial random partitioning algorithm. The spatial random partitioning algorithm includes the Voronoi diagram algorithm, the Delaunay triangulation algorithm and its dual graph or a competitive growth algorithm based on a distance function.

[0011] In the above-described method for generating a privacy film microstructure pattern to suppress moiré patterns, in step S5, the predetermined linewidth is either fixed at 2 micrometers or varies and / or is non-uniform on different line segments.

[0012] In the above-mentioned method for generating a privacy film microstructure pattern to suppress moiré patterns, in step S5, the solidification involves offsetting each grid line along its normal direction to generate a closed polygon.

[0013] A privacy screen microstructure pattern for suppressing moiré patterns is generated using any of the above-described methods for generating a privacy screen microstructure pattern for suppressing moiré patterns.

[0014] The aforementioned privacy film microstructure pattern for suppressing moiré patterns has grid lines that are trimmed at region boundaries and locally connected to maintain the continuity of the overall structure.

[0015] The above-mentioned privacy film microstructure pattern for suppressing moiré patterns is used in privacy films for mobile phones, tablets, laptops, automotive displays, or public displays.

[0016] The microstructure pattern of the privacy film for suppressing moiré patterns, its generation method, and its application have the following three beneficial effects: First, it has a privacy protection function: by constructing microstructured grid lines with a preset height, it physically blocks incident light rays at angles greater than a certain threshold, thereby limiting the viewing angle and achieving privacy protection. The line width and height can be set as needed, balancing the visual controllability of the structure with the adaptability of the manufacturing process. The variability of the line width and height also provides additional freedom for fine-tuning the optical performance.

[0017] Secondly, it features moiré suppression: through a perturbation design of the basic dot matrix spacing, frequency broadening and periodic perturbation are achieved, reducing the spectral peak energy of the regular periodic structure in the spatial frequency domain. This suppresses stable coupling with the pixel period of the display screen, reducing the probability of moiré patterns. By employing a random perturbation strategy, it achieves a structural characteristic of "locally near-regular, overall quasi-irregular," theoretically balancing privacy protection and moiré suppression, avoiding the limitations of traditional regular periodic structures in terms of uniformity and susceptibility to periodic coupling.

[0018] Third, it features flexible design and generation methods: Based on spatial partitioning algorithms, it generates irregular polygonal mesh structures, transforming the structural form from regular boundaries to varied polygonal boundaries, increasing spectral complexity and enhancing anti-interference capabilities. Compared to a single Voronoi diagram, the multiple selectable generation algorithms provide a richer structure library, increasing the flexibility of the proposed solution. Attached Figure Description

[0019] Figure 1 This is a flowchart of the method for generating microstructure patterns for privacy films used to suppress moiré patterns according to the present invention.

[0020] Figure 2 This is a schematic diagram of the process for generating microstructure patterns in a privacy film used to suppress moiré patterns according to the present invention.

[0021] Figure 3 This is a schematic diagram illustrating the principle by which the microstructure pattern of the privacy film used in this invention to suppress moiré patterns can suppress moiré patterns. Detailed Implementation

[0022] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Specific Implementation Method 1

[0024] The following is a specific implementation of the method for generating microstructure patterns for privacy films to suppress moiré patterns according to the present invention.

[0025] The flowchart of the method for generating the microstructure pattern of the privacy film for suppressing moiré patterns in this specific embodiment is as follows: Figure 1 As shown, it includes the following steps: Step S1: Generate a basic dot matrix in a region to be designed. The basic dot matrix is ​​arranged in two dimensions in the x and y directions and has a basic spacing. Step S2: Apply a random perturbation to the position of each point in the basic dot matrix, so that each point deviates from the original grid position, and the distance between two adjacent points after the perturbation is within a preset range; Step S3: Using the perturbed point set as seed points, generate an irregular polygonal mesh structure; Step S4: Extract the grid lines from the irregular polygonal grid structure as the microstructure lines of the privacy film; Step S5: Solidify the microstructure lines into polygonal lines according to a predetermined line width to form a privacy film microstructure pattern.

[0026] The process diagrams corresponding to steps S1 to S5 are as follows: Figure 2 As shown.

[0027] The following points need to be explained: (1) Region definition Define the boundary range of the area to be designed, which can be any applicable size. For ease of explanation, the area will be referred to as the "design area" in the following description. The design area can be a rectangle, square, circle, or other suitable shape.

[0028] (2) Basic lattice generation A basic dot matrix is ​​generated within the design area. As a preferred example, the basic dot matrix has a spacing of 10 micrometers and is arranged in a two-dimensional orthogonal pattern. That is, dots are arranged at a spacing of 10 micrometers in both the x and y directions. The number of nodes in the basic dot matrix can be determined according to the size of the design area.

[0029] (3) Disturbance design A random perturbation is applied to the position of each node in the base lattice, causing the actual position of each node to deviate from the base lattice position. As a preferred example, the perturbation amplitude is designed to be ±2.5 micrometers, so that the actual period after perturbation is distributed in the range of 7 to 12 micrometers.

[0030] (4) Generation of irregular polygonal mesh structure Using the perturbed point set as seed points, an irregular polygonal mesh structure is generated through a spatial partitioning algorithm. The preferred spatial partitioning algorithm is the Voronoi diagram algorithm, which divides the design region into several Voronoi elements. Alternatively, the Delaunay triangulation algorithm can be used to generate a triangular mesh, and its edges or dual graphs can be extracted as structural lines; or a competition growth algorithm based on a distance function can be used to simulate the crystal growth boundary. This process can be implemented using numerical computation software, such as the scipy.spatial.Voronoi or scipy.spatial.Delaunay algorithms in Python, or other equivalent algorithms.

[0031] (5) Grid line extraction The grid lines in the generated irregular polygonal mesh structure are extracted as the microstructure lines of the privacy film. For lines that cross the area boundary, a clipping process is applied to retain the effective portion within the area.

[0032] (6) Solidification of lines The extracted mesh lines are solidified according to a predetermined line width. Solidification specifically involves offsetting each mesh line by a certain distance along the normal direction, generating a rectangular polygonal line. Adjacent lines can be merged, deduplicated, or locally connected to avoid overlap or discontinuity. The line width can be set to 2 micrometers, or adjusted on certain segments based on local density or position to create variable-width lines.

[0033] (7) Data output The polygonal lines are then compiled into pattern data that can be used to guide manufacturing. This data includes information on the dot matrix generation area, grid lines, and line widths.

[0034] (8) Structural verification Theoretical analysis and simulation verification are performed based on the generated pattern data. It is recommended to conduct two-dimensional Fourier transform analysis on the structure to observe its spatial spectral distribution; compared with traditional regular periodic structures, the spectral peaks of the structure of this invention are smoother and the bandwidth is wider. Specific Implementation Method Two The following are specific embodiments of the privacy film microstructure pattern for suppressing moiré patterns according to the present invention.

[0036] The method for generating a privacy film microstructure pattern for suppressing moiré patterns, as described in Specific Embodiment 1, yields a privacy film microstructure pattern for suppressing moiré patterns. This privacy film microstructure pattern for suppressing moiré patterns possesses privacy protection functionality, moiré pattern suppression functionality, and a flexible design and generation method, as follows: It features privacy protection: by constructing microstructured grid lines with a preset height, it physically blocks incident light rays at angles greater than a specific distance, thereby limiting the viewing angle and achieving privacy protection. The line width and height can be set as needed, balancing visual controllability of the structure with manufacturing process adaptability. The variability of line width and height also provides additional freedom for fine-tuning optical performance.

[0037] It has the function of suppressing moiré patterns: To verify the effect of the above-mentioned microstructure pattern on suppressing moiré patterns, numerical simulation was performed. In the simulation, the basic lattice spacing was set to 10 micrometers, such as... Figure 3 As shown in a), independent random perturbations with amplitudes of ±2.5 μm are applied in the x and y directions, respectively, so that the spacing between adjacent points after the perturbation is distributed in the range of 7 μm to 12 μm; the line width of the microstructure is fixed at 2 μm. Based on the generated... Figure 3 The spatial spectrum of the privacy film microstructure pattern shown in b) was calculated using a two-dimensional Fourier transform and compared with the spectrum of a regular periodic structure with the same base spacing. The results are shown in the figures below. Figure 3 c) and such Figure 3 As shown in d). Simulation results show that in the spatial spectrum of the microstructure pattern of the present invention, Figure 3 c) The spectral peaks that were originally concentrated in the regular periodic structure are significantly broadened, the peak energies are greatly reduced, and the spectral distribution tends to be flatter. Figure 3 d) No isolated sharp spectral peaks were observed. This indicates that the irregular polygonal mesh structure formed by perturbing the basic lattice spacing effectively disrupts the conditions for stable coupling with periodic structures such as the display pixel array, significantly reducing the probability of moiré patterns and achieving the expected moiré pattern suppression effect.

[0038] It features flexible design and generation methods: based on a spatial partitioning algorithm, it generates irregular polygonal mesh structures, transforming the structural form from regular boundaries to varied polygonal boundaries, increasing spectral complexity and enhancing anti-interference capabilities. Compared to a single Voronoi diagram, the multiple selectable generation algorithms provide a richer structure library, increasing the flexibility of the proposed solutions. Specific Implementation Method 3 The following are specific embodiments of the application of the microstructure pattern of the privacy film for suppressing moiré patterns according to the present invention.

[0040] The privacy film microstructure pattern for suppressing moiré patterns described in Specific Implementation 1 is used for privacy films on mobile phones, tablets, laptops, vehicle displays, or public displays.

[0041] It should be noted that the above are merely specific embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

[0042] It should also be noted that all the technical features listed in the above specific embodiments can be arranged and combined, as long as they are not contradictory. Those skilled in the art can exhaustively calculate the result of each arrangement and combination based on the mathematical knowledge of permutations and combinations learned in high school. All the results of permutations and combinations should be understood as being disclosed in this application.

Claims

1. A method for generating a microstructure pattern for a privacy film to suppress moiré patterns, characterized in that: Includes the following steps: Step S1: Generate a basic dot matrix in a region to be designed. The basic dot matrix is ​​arranged in two dimensions in the x and y directions and has a basic spacing. Step S2: Apply a random perturbation to the position of each point in the basic dot matrix, so that each point deviates from the original grid position, and the distance between two adjacent points after the perturbation is within a preset range; Step S3: Using the perturbed point set as seed points, generate an irregular polygonal mesh structure; Step S4: Extract the grid lines from the irregular polygonal grid structure as the microstructure lines of the privacy film; Step S5: Solidify the microstructure lines into polygonal lines according to a predetermined line width to form a privacy film microstructure pattern.

2. The method for generating a privacy film microstructure pattern for suppressing moiré patterns according to claim 1, characterized in that: In step S1, the basic spacing is 10 micrometers.

3. The method for generating a privacy film microstructure pattern for suppressing moiré patterns according to claim 1, characterized in that: In step S2, the amplitude of the random disturbance is ±2.5 micrometers, the random disturbance is generated independently in the x and y directions respectively, and the disturbance distribution function is any one of uniform distribution, normal distribution or mixed distribution, and the preset range is 7 micrometers to 12 micrometers.

4. The method for generating a privacy film microstructure pattern for suppressing moiré patterns according to claim 1, characterized in that: In step S3, an irregular polygonal mesh structure is generated by a spatial random partitioning algorithm, which includes the Voronoi diagram algorithm, the Delaunay triangulation algorithm and its dual graph or a competitive growth algorithm based on a distance function.

5. The method for generating a privacy screen microstructure pattern for suppressing moiré patterns according to claim 1, characterized in that: In step S5, the predetermined linewidth is either fixed at 2 micrometers or varies and / or is non-uniform on different line segments.

6. The method for generating a privacy film microstructure pattern for suppressing moiré patterns according to claim 1, characterized in that: In step S5, the solidification is to offset each grid line along its normal direction to generate a closed polygon.

7. A privacy film microstructure pattern for suppressing moiré patterns, characterized in that: The microstructure pattern of the privacy film for suppressing moiré patterns is generated using the method described in any one of claims 1-6.

8. The privacy film microstructure pattern for suppressing moiré patterns according to claim 7, characterized in that: The grid lines are trimmed at the region boundaries and locally connected to maintain the continuity of the overall structure.

9. A privacy film microstructure pattern for suppressing moiré patterns according to claim 7, characterized in that: Privacy screen protectors for mobile phones, tablets, laptops, in-vehicle displays, or public displays.

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