A laser homogenizer

Abstract

The laser homogenizer provided by the present invention has a surface composed of a plurality of curved microlenses, the aperture of any of the curved microlenses is a polygon, the number of sides of the polygon is randomly set, the position of the center point of any of the curved microlenses is randomly set, the position of the aperture edge intersection of any of the curved microlenses is random, and the curved microlenses of adjacent apertures are closely arranged. Since the laser homogenizer provided by the present invention has each curved microlens randomly distributed in shape, aperture side number, aperture center position, and aperture edge position, its interference is also random when the laser is incident, and no interference phenomenon of light and dark changes is formed in the far field, thereby overcoming the interference problem in the traditional periodic microlens array light homogenization.

Description

Technical Field

[0001] The invention relates to the technical field of optical devices, and in particular to a laser homogenizer. Background Art

[0002] Laser homogenizers are widely used in laser lighting, laser television, laser medical treatment, 3D imaging, laser processing, etc. There are two main ways to homogenize lasers: one is to use a geometric homogenization system with a periodically arranged microlens array; the other is to use a binary step-type diffraction homogenization structure. Due to the strong periodicity of the structure of the microlens array, under laser irradiation, it produces a strong interference effect due to its periodicity, forming a strong interference enhancement or weakening area in the far field, which seriously affects the homogenization effect; the binary step-type diffraction structure is very sensitive to the step depth because its zero-order energy is extremely sensitive to the step depth, which makes it difficult to eliminate the zero-order, especially when the angle of the homogenized light spot is large, the strong light generated by the zero-order diffraction will be much higher than other areas, so its application is limited. Summary of the invention

[0003] In view of this, it is necessary to provide a laser homogenizer that overcomes the limitations of traditional periodic microlens geometric laser homogenization and binary diffraction homogenization structure in view of the defects of the prior art.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] A laser homogenizer, the surface of which is composed of a plurality of curved microlenses, the aperture of any one of the curved microlenses is a polygon, the number of sides of the polygon is randomly set, the position of the center point of any one of the curved microlenses is randomly set, the position of the intersection point of the aperture edge of any one of the curved microlenses is random, and the curved microlenses of adjacent apertures are closely arranged.

[0006] In some preferred embodiments, the laser homogenizer is made of optical plastic or optical glass.

[0007] In some preferred embodiments, the shape of each curved microlens in the laser homogenizer is different.

[0008] In some preferred embodiments, two adjacent polygons share a common edge.

[0009] In some preferred embodiments, the curved microlenses include convex curved microlenses and concave curved microlenses.

[0010] The advantages of the present invention using the above technical solution are:

[0011] The laser homogenizer provided by the present invention has a surface composed of a plurality of curved microlenses, the aperture of any of the curved microlenses is a polygon, the number of sides of the polygon is randomly set, the position of the center point of any of the curved microlenses is randomly set, the position of the aperture edge intersection of any of the curved microlenses is random, and the curved microlenses of adjacent apertures are closely arranged. Since the laser homogenizer provided by the present invention has each curved microlens randomly distributed in shape, aperture side number, aperture center position, and aperture edge position, its interference is also random when the laser is incident, and no interference phenomenon of light and dark changes is formed in the far field, thereby overcoming the interference problem in the traditional periodic microlens array light homogenization.

[0012] In addition, since the laser homogenizer provided by the present invention modulates the laser phase through the gradient of each curved microlens, the zero-order energy is insensitive to the absolute depth of the sub-lens, and there is no zero-order light spot with obvious energy difference, which overcomes the zero-order diffraction phenomenon in the traditional binary diffraction homogenizer and makes the homogenized light spot more uniform. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] 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.

[0014] Figure 1 The random distribution of the center points of the curved micro-lenses of the laser homogenizer provided by the embodiment of the present invention;

[0015] Figure 2 The random distribution of the aperture edge of the curved microlens of the laser homogenizer provided by the embodiment of the present invention;

[0016] Figure 3 The three-dimensional structure morphology of the concave curved microlens provided by the embodiment of the present invention;

[0017] Figure 4 The three-dimensional structure morphology of the convex curved microlens provided in the embodiment of the present invention;

[0018] Figure 5 An example of far-field emission light field distribution of a concave curved surface structure provided in an embodiment of the present invention;

[0019] Figure 6 An example of the far-field output light field distribution of the convex curved surface structure provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0020] 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.

[0021] The present invention provides a laser homogenizer, the surface of which is composed of a plurality of curved microlenses, the aperture of any one of the curved microlenses is a polygon, the number of sides of the polygon is randomly set, the position of the center point of any one of the curved microlenses is randomly set, the position of the intersection point of the aperture edge of any one of the curved microlenses is random, and the curved microlenses of adjacent apertures are closely arranged.

[0022] It can be understood that, due to the laser homogenizer provided by the present invention, each curved microlens is randomly distributed in shape, number of aperture sides, aperture center position, and aperture edge position. Therefore, its interference is also random when the laser is incident, and no interference phenomenon of light and dark changes is formed in the far field, thereby overcoming the interference problem in the traditional periodic microlens array homogenization.

[0023] In some preferred embodiments, the laser homogenizer is made of optical plastic or optical glass.

[0024] In some preferred embodiments, the shape of each curved microlens in the laser homogenizer is different.

[0025] In some preferred embodiments, the polygons where two closely arranged curved micro-lenses are located share a side.

[0026] In some preferred embodiments, the curved microlenses include convex curved microlenses and concave curved microlenses.

[0027] It can be understood that the far-field spot size of the laser homogenizer is determined by the aperture size and the vector height of the curved microlens, and the light field distribution uniformity of the far-field spot of the laser homogenizer is determined by the surface shape of the curved microlens.

[0028] It can be understood that in the laser homogenizer provided by the present invention, the surface shape of each curved microlens is a curved surface, and the laser phase is modulated by the gradient of the curved surface. Therefore, the zero-order energy is insensitive to the absolute depth of the sub-lens, and there is no zero-order light spot with obvious energy difference. This overcomes the zero-order diffraction phenomenon in the traditional binary diffraction homogenizer, and the homogenized light spot is more uniform.

[0029] The technical solution of the present invention is described in detail below in conjunction with specific embodiments.

[0030] Embodiment 1:

[0031] In this embodiment, the laser homogenizer is made of optical UV plastic, and the center point of the curved microlens of the laser homogenizer satisfies Figure 1 The random distribution shown; the distribution of the aperture edge of the curved microlens of the laser homogenizer satisfies Figure 2 The random distribution shown in FIG. 1 shows that the number of edges of each sub-aperture is not fixed, the edge shape of each sub-aperture is different, and two adjacent sub-apertures are closely arranged and share one edge. The average aperture of the structure in the horizontal direction is 47 microns, and the average aperture in the vertical direction is 35 microns. The three-dimensional surface distribution of the curved microlens of the laser homogenizer is shown in FIG. Figure 3 As shown in the figure, each curved microlens aperture is a concave continuous curved lens, and the size of each sub-aperture is random. Under the incident parallel laser with a wavelength of 940nm, the homogenous light spot of the homogenizer at 1 meter is as follows Figure 5 As shown, the light spot is generally close to a rectangle, there is no interference between the zero order and the light and dark distribution, and the internal light distribution is uniform.

[0032] Embodiment 2:

[0033] In this embodiment, the laser homogenizer is made of optical glass; the center points of the curved microlenses of the laser homogenizer are randomly distributed; the edges of the curved microlenses of the laser homogenizer are randomly distributed, the number of edges of each sub-aperture is not fixed, the edge shape of each sub-aperture is different, two adjacent sub-apertures are closely arranged and share one edge, the average aperture of the curved microlenses in the horizontal direction is 20 microns, and the average aperture in the vertical direction is 30 microns; the inner diameter of each curved microlens of the laser homogenizer is as follows Figure 4 The continuous curved surface shown in FIG. 1 is a continuous curved surface; under the incident parallel laser with a wavelength of 650 nm, the homogenized light spot of the laser homogenizer at 1 meter is as follows: Figure 6 As shown, the uniform light spot is close to a rectangle as a whole, there is no interference between the zero order and the bright and dark distribution, and the internal light distribution is uniform.

[0034] Of course, the laser homogenizer 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 ordinary technicians in the field.

Claims

1. A laser homogenizer, characterized in that: The surface of the laser homogenizer is composed of a plurality of curved micro-lenses, the aperture of any of the curved micro-lenses is a polygon, the number of sides of the polygon is randomly set, the position of the center point of any of the curved micro-lenses is randomly set, the position of the intersection point of the aperture edge of any of the curved micro-lenses is random, and the curved micro-lenses of adjacent apertures are closely arranged: The shape of each curved microlens in the laser homogenizer is different; Two adjacent polygons share an edge; The laser phase is modulated by the gradient of the curved surface, making the zero-order energy insensitive to the absolute depth of the sub-lens.

2. The laser homogenizer according to claim 1, characterized in that: The material of the laser homogenizer is optical plastic or optical glass.

3. The laser homogenizer according to claim 1, characterized in that: The curved surface microlenses include convex curved surface microlenses and concave curved surface microlenses.

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