A laser beam splitter
By using a periodically arranged Fresnel ring array on the laser beam splitter, Fresnel folding is used to reduce the microlens vector height, solving the problem of difficult processing of large-angle beam splitting patterns and limited beam splitting angles, achieving the generation of large-angle uniform beam splitting patterns and the uniformity of central zero-order energy distribution.
Patent Information
- Application Number
- CN201910026487.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2019-01-11
- Publication Date
- 2025-05-16
- Estimated Expiration
- 2039-01-11
AI Technical Summary
When the existing microlens array beam splitter based on continuous curved surfaces obtains large angle diffraction beam splitters, the vector height of the microlens is high, which makes processing difficult. The beam splitting angle of the traditional binary diffraction beam splitters is limited by the characteristic size, and the energy distribution of the central zero-order spot is uneven.
The Fresnel ring array with periodic arrangement is used as the surface structure of the laser beam splitter, and the vector height of the three-dimensional curved microlens is reduced through Fresnel folding, and the Fresnel ring array with rectangular or diamond dislocation is used to achieve the generation of a large angle uniform beam splitting pattern.
The generation of a large-angle beam splitting pattern is achieved. The beam splitting angle is not limited by the characteristic size, and the central zero-level energy distribution is uniform, which overcomes the problems of high processing difficulty and limited beam splitting angle in traditional technology.
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Figure CN109633917B_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of optical devices, and in particular to a laser beam splitter. Background Art
[0002] Laser beam splitters are widely used in laser processing, three-dimensional measurement, optical alignment, optical communications, lighting display and other fields. Traditional laser beam splitters use binary optics to obtain laser beam splitting patterns through special step-type phase modulation. However, the beam splitting pattern angle of this diffraction beam splitter is limited by the lateral characteristic size of the step, and the processing of large-angle beam splitting is difficult; secondly, the slight error in the step depth will cause the beam splitter to produce a central zero-order light spot with much higher energy than other orders, resulting in uneven energy distribution of its beam splitting point matrix and limited use. In order to solve the above problems, a new type of microlens array beam splitter based on continuous surfaces was proposed. However, in order to obtain large-angle diffraction beam splitting, the corresponding microlens has a large sagittal height, which is difficult to process. Summary of the invention
[0003] In view of this, it is necessary to provide a laser beam splitter that can solve the difficult processing problem caused by the large vector height of the existing microlens array beam splitter based on continuous curved surface in order to address the defects of the existing technology.
[0004] To achieve the above object, the present invention adopts the following technical solutions:
[0005] A laser beam splitter, the surface of which is composed of a periodically arranged Fresnel ring array.
[0006] In some preferred embodiments, the Fresnel periodic array is obtained by phase folding of the corresponding microlenses.
[0007] In some preferred embodiments, the Fresnel ring array is arranged in a rectangular arrangement or a diamond staggered arrangement.
[0008] In some preferred embodiments, the laser beam splitter generates an array-arranged beam splitting dot pattern in the far field under laser incidence.
[0009] In some preferred embodiments, there is no central zero-order light spot in the beam splitting dot matrix pattern whose energy is much greater than that of other orders.
[0010] The advantages of the present invention using the above technical solution are:
[0011] The laser beam splitter provided by the present invention is composed of Fresnel rings arranged in an array, and utilizes Fresnel folding to reduce the sagittal height of a three-dimensional curved surface microlens, has a shallow processing depth, and is easy to manufacture.
[0012] In addition, the laser beam splitter provided by the present invention can obtain the same diffraction effect as a three-dimensional curved microlens array, that is, a large-angle beam splitting pattern with good uniformity is produced in the far field, and the beam splitting angle is not limited by the characteristic size, thus overcoming the problem that the beam splitting angle of the traditional binary diffraction beam splitter is limited by the characteristic size.
[0013] In addition, the central zero-order energy of the laser beam splitter provided by the present invention is insensitive to both the micro-arc height and the wavelength, thus overcoming the central zero-order bright spot that is difficult to overcome in a traditional binary diffraction beam splitter. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0015] Figure 1 A schematic diagram of the structure of a laser beam splitter provided in Example 1 of the present invention;
[0016] Figure 2 A schematic diagram of the structure of a laser beam splitter provided in Example 2 of the present invention;
[0017] Figure 3 A schematic diagram of the structure of a laser beam splitter provided in Example 3 of the present invention;
[0018] Figure 4 A schematic diagram of the structure of a laser beam splitter provided in Example 4 of the present invention;
[0019] Figure 5 A laser beam splitting dot matrix diagram of the laser beam splitter provided in embodiments 1 and 2 of the present invention in the far field;
[0020] Figure 6 This is a laser beam splitting dot matrix diagram of the laser beam splitter provided in embodiments 3 and 4 of the present invention in the far field. DETAILED DESCRIPTION
[0021] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0022] The invention provides a laser beam splitter, the surface of which is composed of a periodically arranged Fresnel ring array.
[0023] It can be understood that the period of the Fresnel ring array is determined by the incident laser wavelength, the beam splitting angle, and the grating equation.
[0024] In some preferred embodiments, the Fresnel periodic array is obtained by phase folding of the corresponding microlenses.
[0025] In some preferred embodiments, the arrangement of the Fresnel ring array is a rectangular arrangement or a diamond staggered arrangement, and the staggered angle is determined by the staggered angle of the beam splitting point array.
[0026] In some preferred embodiments, the Fresnel rings in each period unit are obtained by phase folding.
[0027] It can be understood that, under the incident laser, the laser beam splitting device will generate an array-arranged beam splitting dot pattern in the far field, and in the dot-array beam splitting pattern, there is no central zero-order light spot whose energy is much greater than that of other orders.
[0028] It can be understood that the laser beam splitting device can obtain the same diffraction effect as the three-dimensional curved microlens array, that is, it can produce a large-angle beam splitting pattern with good uniformity in the far field, and the beam splitting angle is not limited by the characteristic size, which overcomes the problem that the beam splitting angle of the traditional binary diffraction beam splitter is limited by the characteristic size; and the central zero-order energy is insensitive to the micro-arc height and wavelength, which overcomes the central zero-order bright spot that is difficult to overcome with the traditional binary diffraction beam splitter.
[0029] The laser beam splitter provided by the present invention is composed of Fresnel rings arranged in an array, and utilizes Fresnel folding to reduce the sagittal height of a three-dimensional curved surface microlens, has a shallow processing depth, and is easy to manufacture.
[0030] The technical solution of the present invention is described in detail below in conjunction with specific embodiments.
[0031] Embodiment 1:
[0032] See also Figure 1 , is a schematic diagram of the structure of the laser beam splitter provided in Example 1 of the present invention.
[0033] In this embodiment, the internal structure of the laser beam splitter is a Fresnel periodic array with an array period of 6 microns. The structure and array arrangement of the Fresnel periodic array are as follows: Figure 1 The rectangular arrangement shown in the figure; the Fresnel periodic array is obtained by 2π phase folding of the corresponding microlens; at a laser wavelength of 830nm, the far-field beam splitting lattice generated at a distance of 100mm is as follows Figure 5 As shown, the energy distribution of the beam splitting lattice is uniform, there is no central zero level with obvious brightness difference, and the lattice satisfies the rectangular arrangement.
[0034] Embodiment 2:
[0035] See also Figure 2 , is a schematic diagram of the structure of the laser beam splitter provided in Example 2 of the present invention.
[0036] In this embodiment, the internal structure of the laser beam splitter is a Fresnel ring array with an array period of 6 microns; the structure and array arrangement of the Fresnel ring array are as follows: Figure 2 The rectangular arrangement shown in the figure; the Fresnel ring array is obtained by 4π phase folding of the corresponding microlens; at a laser wavelength of 830nm, the far-field beam splitting dot matrix generated at a distance of 100mm is as follows Figure 5 As shown, the energy distribution of the beam splitting lattice is uniform, there is no central zero level with obvious brightness difference, and the lattice satisfies the rectangular arrangement.
[0037] Embodiment 3:
[0038] See also Figure 3 , is a schematic diagram of the structure of the laser beam splitter provided in Example 3 of the present invention.
[0039] In this embodiment, the internal structure of the laser beam splitter is a Fresnel ring array with an array period of 8 microns; the structure and array arrangement of the Fresnel ring array are as follows: Figure 3 The diamond-shaped staggered arrangement shown in the figure; the Fresnel ring array is obtained by 2π phase folding of the corresponding microlens; at a laser wavelength of 940nm, the far-field beam splitting dot matrix generated at a distance of 300mm is as follows Figure 6 As shown, the energy distribution of the beam splitting lattice is uniform, there is no central zero level with obvious brightness difference, and the lattice satisfies the staggered arrangement.
[0040] Embodiment 4:
[0041] See also Figure 4 , is a schematic diagram of the structure of the laser beam splitter provided in Example 4 of the present invention.
[0042] In this embodiment, the internal structure of the laser beam splitter is a Fresnel ring array with an array period of 8 microns; the structure and array arrangement of the Fresnel ring array are as follows: Figure 4 The diamond-shaped staggered arrangement shown in the figure; the Fresnel ring array is obtained by 4π phase folding of the corresponding microlens; at a laser wavelength of 940nm, the far-field beam splitting dot matrix generated at a distance of 300mm is as follows Figure 6 As shown, the energy distribution of the beam splitting lattice is uniform, there is no central zero level with obvious brightness difference, and the lattice satisfies the staggered arrangement.
[0043] Of course, the laser beam splitter of the present invention may also have a variety of changes and modifications, and is not limited to the specific structure of the above-mentioned embodiment. In short, the protection scope of the present invention should include those changes or substitutions and modifications that are obvious to those of ordinary skill in the art.
Claims
1. A laser beam splitter, characterized in that: The surface of the laser beam splitter is composed of a periodically arranged Fresnel ring array; The Fresnel ring is a microlens with a micro-arc surface obtained by 2π phase folding or 4π phase folding; The Fresnel ring array generates a diffraction-based beam splitting lattice pattern in the far field under laser incidence, and the array period is 6 microns or 8 microns; the period of the Fresnel ring array is determined by the incident laser wavelength and the beam splitting angle through the grating equation; In the beam splitting dot matrix pattern, there is no central zero-order light spot whose energy is much greater than that of other orders.
2. The laser beam splitter according to claim 1, characterized in that The Fresnel ring array is arranged in a rectangular arrangement or a diamond staggered arrangement.
3. The laser beam splitter according to claim 1, characterized in that The beam splitting dot pattern is arranged in an array.
Citation Information
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