CN114895505B - Projection module for realizing laser lattice - Google Patents
Projection module for realizing laser lattice Download PDFInfo
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
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- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/10—Beam splitting or combining systems
- G02B27/12—Beam splitting or combining systems operating by refraction only
- G02B27/126—The splitting element being a prism or prismatic array, including systems based on total internal reflection
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- G—PHYSICS
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Abstract
The application discloses a projection module for realizing a laser lattice, which comprises a laser light source, a collimation device and a micro-prism optical element, wherein the micro-prism optical element is provided with two main surfaces for incidence and emergence of light rays, the two main surfaces are opposite to each other, at least one main surface comprises a plurality of micro-prism surfaces with different inclination angles, the refraction of the collimated light beams is carried out through the micro-prisms, the collimated light beams are split, and the split light beams obtained by splitting the same collimated light beam are projected along a plurality of different preset projection angles, so that the laser lattice is obtained. The application also discloses a microprism optical element. According to the embodiment of the application, the laser is split based on the optical refraction principle to obtain the laser lattice, so that the laser energy utilization efficiency can be improved, the stray light generated by diffraction can be obviously reduced, the design is more flexible, and the processing and manufacturing are easier.
Description
The application is a divisional application of patent application with the application number 202011409470.5, the application date 2020, 12 months and 3 days, jiaxing control light photoelectric technology Co., ltd, and the application name of microprism optical element and projection module for realizing laser lattice.
Technical Field
The present invention relates generally to three-dimensional sensing technology, and in particular to a microprism optical element for projecting a laser lattice based on a laser collimated beam and a projection module for implementing the laser lattice.
Background
Structured light three-dimensional sensing technology is increasingly used in consumer electronics, robotics, logistics, industrial detection and other fields. Among structured light for three-dimensional sensing technology, laser lattice is the most widely used.
When a DOE (diffraction optical element, DIFFRACTIVE OPTICAL ELEMENT) is used to design a laser beam splitting lattice, the DOE is a binary phase modulation device, so that the DOE has the conditions of relatively low optical efficiency, complex design and the like, and the DOE is designed with relatively high requirements on a used computing platform and high requirements on processing and manufacturing.
Therefore, a new technology for obtaining the laser lattice is needed.
Disclosure of Invention
The invention aims to provide a projection module for splitting laser based on an optical refraction principle to obtain a laser lattice and a microprism optical element for projecting the laser lattice, which at least partially overcome the defects in the prior art.
According to one aspect of the present invention, there is provided a projection module for realizing a laser lattice, the projection module including a laser light source, a collimating device, and a micro-prism optical element. The laser light source emits a laser beam. A collimating device receives the laser beam and collimates it to form a substantially collimated beam. The micro prism optical element has two main faces for light to enter and exit, the two main faces are opposite to each other, at least one main face comprises a plurality of micro prism faces with different inclination angles, the micro prism optical element receives the collimated light beam, the collimated light beam is split by refraction of the plurality of micro prisms, and the split light beam obtained by splitting the same collimated light beam is projected along a plurality of different preset projection angles to obtain a laser lattice.
In an advantageous embodiment, the microprismatic optical element has a profile dimension substantially identical to the beam diameter of the collimated beam.
Preferably, the plurality of micro prism faces have mutually different inclination angles, and the plurality of micro prism faces have light receiving areas adapted to the lateral light intensity distribution of the collimated light beam so that the respective micro prism faces can receive substantially the same luminous flux.
In an advantageous embodiment, the laser light source comprises a laser array for emitting a plurality of laser beams; the collimating device receives the plurality of laser beams and collimates the plurality of laser beams to form a plurality of corresponding collimated beams; and the plurality of micro-prism facets of the micro-prism optical element split each of the plurality of collimated light beams.
In an advantageous embodiment, the plurality of laser beams emitted by the laser array form an initial lattice, and assuming that a laser lattice formed by the plurality of microprisms splitting a single laser beam facing a single laser beam is a single-point beam splitting lattice, the laser lattice projected by the plurality of microprisms splitting the plurality of collimated light beams has an array structure formed by arranging the initial lattice according to positions of points in the single-point beam splitting lattice.
In an advantageous embodiment, the laser light source emits m laser light beams, the plurality of microprism faces of the microprism optical element having n mutually different inclination angles, the plurality of microprism faces being split to project a laser lattice of m×n laser spots.
The laser light source may be a vertical cavity surface emitting laser.
Preferably, the micro-prism optical element comprises a plurality of micro-prism units, each micro-prism unit comprising a plurality of micro-prism faces having different inclination angles.
The several microprismatic units may have the same structure. The several microprismatic units may be arranged periodically. The several microprismatic units may also be arranged non-periodically. Preferably, the several microprismatic units have different dimensions.
In an advantageous embodiment, the plurality of microprismatic faces comprises at least one central face, which is parallel to the other main face. In an advantageous embodiment, the microprismatic faces of each of the microprismatic units comprise a central plane which is parallel to the other main plane. In such embodiments, it is preferred that the microprismatic faces around the central plane are arranged symmetrically with respect to the central plane.
In an advantageous embodiment, the microprismatic faces in each of said microprismatic units are contiguous in a substantially continuous manner.
According to another aspect of the present invention, there is provided a microprism optical element for projecting a laser lattice based on a laser collimated beam, having two main faces for light incidence and emergence, the two main faces being opposite to each other, wherein at least one main face includes a plurality of microprism faces having different inclination angles. The microprism optical element is configured to, upon receiving at least one laser collimated beam having a beam diameter substantially the same as its principal face size, split the collimated beam by refraction of the collimated beam by the plurality of microprisms and cause a plurality of split beams resulting from the splitting of the same collimated beam to be projected along a plurality of different predetermined projection angles to form a laser lattice.
In an advantageous embodiment, the maximum contour dimension of the two main faces is less than or equal to 5mm.
In an advantageous embodiment, the plurality of microprismatic faces have mutually different inclination angles.
Preferably, the plurality of micro-prism faces have a light receiving area adapted to the light intensity distribution of the incident laser beam so that each micro-prism face can receive substantially the same light flux.
In an advantageous embodiment, the plurality of microprismatic faces comprises at least one central face, which is parallel to the other main face.
Preferably, the micro-prism optical element comprises a plurality of micro-prism units arranged in an array, each micro-prism unit comprising a plurality of micro-prism faces having different tilt angles.
The several microprismatic units may be arranged periodically and have the same structure.
Preferably, the several microprismatic units are non-periodically arranged and have the same structure and different dimensions.
In an advantageous embodiment, the microprismatic faces in the microprismatic units form a 3x3 array.
In an advantageous embodiment, the microprism unit has a rotationally symmetrical structure for splitting a plurality of beams of light arranged in a circular ring from the collimated beam of laser light.
According to the projection module and the micro-prism optical element used for the projection module, the laser is split based on the optical refraction principle to obtain the laser lattice. Therefore, the laser energy utilization efficiency can be improved, stray light generated by diffraction is obviously reduced, the design is more flexible, and the processing and the manufacturing are easier.
Drawings
Other features, objects and advantages of the present invention will become more apparent upon reading of the detailed description of non-limiting embodiments, made with reference to the following drawings in which:
FIG. 1 is a schematic view of a projection module according to a first embodiment of the invention;
FIG. 2 is a schematic block diagram of one example of a microprismatic optical element according to an embodiment of the invention that may be used in the projection module shown in FIG. 1;
FIGS. 3 and 4 are schematic diagrams of light splitting achieved with different angles of inclination of the micro-prism facets of a micro-prism optical element according to embodiments of the present invention;
FIG. 5 schematically illustrates an example of a laser lattice obtained using the projection module of FIG. 1;
FIG. 6 is a schematic diagram of a projection module according to a second embodiment of the invention;
FIG. 7 is a schematic diagram of an initial array of laser beams formed by an array of lasers;
FIG. 8 schematically illustrates an example of a laser lattice obtained using the projection module of FIG. 6;
FIG. 9 is a schematic diagram of a projection module according to a third embodiment of the invention;
FIG. 10 is a schematic block diagram of one example of a microprismatic optical element that may be used in the projection module of FIG. 9;
FIG. 11 is an exemplary diagram of a laser array obtained using the projection module of FIG. 9;
FIG. 12 is a schematic view of a projection module according to a fourth embodiment of the invention;
FIG. 13 is a schematic view of a variation of the microprismatic optical element of FIG. 10;
FIG. 14 is a schematic view of a variation of the microprismatic optical element of FIG. 2; and
Fig. 15 schematically illustrates an example of a laser lattice obtained using the microprismatic optical element of fig. 14.
Detailed Description
The invention is described in further detail below with reference to the drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. For convenience of description, only parts related to the invention are shown in the drawings.
It should be noted that, without conflict, the embodiments of the present application and features of the embodiments may be combined with each other. The application will be described in detail below with reference to the drawings in connection with embodiments.
First, a projection module for projecting a laser beam lattice and a micro-prism optical element according to a first embodiment of the present invention will be described with reference to fig. 1 to 5.
Fig. 1 is a schematic view of a projection module 1 according to a first embodiment of the invention. As shown in fig. 1, the projection module 1 includes a laser light source 10, a collimator device 20, and a micro prism optical element 30. The laser light source 10 emits a laser beam LB. The collimating device 20 is arranged to receive and collimate the laser beam LB to form a substantially collimated beam CB.
The collimating lens device comprising lenses shown in the collimating device 20 of fig. 1 is only an example, and the collimating device 20 may be of other forms, such as a single lens or a multi-piece lens, or may be a waveguide and/or micro-nano structure based collimating device.
The micro prism optical element 30 has two main faces for light incident and emergent, the two main faces being opposite to each other, wherein at least one main face includes a plurality of micro prism faces having different inclination angles. This will be described in more detail below in connection with examples.
The micro-prism optical element 30 receives the collimated light beam CB, splits the collimated light beam CB by refraction of the collimated light beam CB by a plurality of micro-prisms, and obtains a plurality of split light beams BM1, BM2, BM3, which are projected along a plurality of different projection angles.
It can be seen that, unlike the projection of a laser lattice based on the diffraction of a binary optical element DOE, according to an embodiment of the present invention, there is provided a technique for splitting laser light based on the principle of optical refraction to obtain a laser lattice, in which a laser spot is split and projected in different directions mainly using a plurality of micro-prism facets with different tilt angles in a micro-prism optical element, resulting in a laser split-lattice. Therefore, the laser energy utilization efficiency can be improved, stray light is obviously reduced, the relative design mode is flexible, and a plurality of limiting requirements do not exist in the processing aspect.
By way of example only and not limitation, FIG. 2 illustrates one example of a micro-prismatic optical element 30 according to an embodiment of the present invention, which micro-prismatic optical element 30 may be used in the projection module shown in FIG. 1. As shown in fig. 2, the micro-prism optical element 30 has two main faces 31, 32 for light to enter and exit; the two main faces 31, 32 are opposite each other. In the example shown in fig. 2, the main surface 31 includes nine microprism surfaces 33, and the nine microprism surfaces 33 have mutually different inclination angles.
For ease of understanding, fig. 3 and 4 illustrate the beam splitting effect of the microprisms facing the light beam at different angles of inclination that the microprism optical element has.
When the micro-prism face 33 is formed on the light incidence side main face 31 of the micro-prism optical element 30, as shown in fig. 3, since the micro-prism face 33 has a certain inclination angle α, the direction of the collimated light beam CB is deflected when the collimated light beam CB enters the micro-prism optical element 30 through the micro-prism face 33, and the deflecting direction of the light incident through the micro-prism faces 33a, 33b of different inclination angles is different.
According to the law of refraction, in the example shown in fig. 3, the following relationship is satisfied between the angle β at which light exits from the micro-prism optical element 30 and the tilt angle α of the corresponding micro-prism face:
Where n 1 is the refractive index of the material of the microprismatic optical element, here assuming a refractive index of 1 for air. In the example shown in fig. 3, the angle β corresponds to the projection angle of the split light beams (e.g., BM1, BM2, BM3 shown in fig. 1).
When the micro-prism face 33 is formed on the light-emitting-side main face 32 of the micro-prism optical element 30, as shown in fig. 4, the collimated light beam CB is refracted at the plurality of micro-prism faces 33a, 33b of the main face 32, and since the micro-prism faces 33a, 33b have different inclination angles α, the direction of deflection of the light emitted via the micro-prism faces 33a, 33b of the different inclination angles is different.
According to the law of refraction, in the example shown in fig. 4, the following relationship is satisfied between the angle γ with respect to the corresponding micro-prism face 33 and the inclination angle α of the micro-prism face when light exits from the micro-prism optical element 30:
sin(γ)＝n1sin(α)
Where n 1 is the refractive index of the material of the microprismatic optical element, here assuming a refractive index of 1 for air. Based on the angle γ, projection angles of the corresponding split light beams (e.g., BM1, BM2, BM3 shown in fig. 1) can be calculated; in the example shown in fig. 4, the projection angle is (γ—α).
Although not shown, it should be understood that in some embodiments, a microprismatic optical element according to embodiments of the present invention may include microprismatic facets with different tilt angles on both major faces of its light incident side and light exit side; in other embodiments, a projection module according to an embodiment of the present invention may use a combination of microprism optical elements including microprism surfaces having different angles of inclination on only one principal surface.
Next, referring back to fig. 2, one numerical example of the microprismatic optical element 30 will be described. In this numerical example, each of the micro prism faces 33 on the main face 31 of the micro prism optical element 30 is designed to project a3×3 rectangular lattice in which the projection angles of each dot are shown in table 1.
Table 1: target lattice projection angle (only size, no orientation)
From the above predetermined projection angle, the inclination angles of the nine micro prism faces 33 can be calculated as shown in table 2 below.
Table 2: micro prism face tilt angle (only size, no orientation)
| 15.71° | 12.17° | 15.71° |
| 9.85° | 0° | 9.85° |
| 15.71° | 12.17° | 15.71° |
As can be seen in combination with table 2 and fig. 2, the plurality of micro-prism faces 33 may include a central plane 33a, the central plane 33a being parallel to the other major face 32 (inclined at 0 ° with respect to the plane in which the major face lies). Further, the plurality of micro prism faces 33 around the center face 33a may be symmetrically arranged with respect to the center face 33 a.
As shown in fig. 5, a 3×3 laser lattice can be projected based on the projection module according to the embodiment of the present invention shown in fig. 1 by using the above-designed micro-prism optical element 30.
In an advantageous embodiment, the plurality of micro-prism facets 33 have a light receiving area that is adapted to the lateral light intensity distribution of the incident light beam such that each micro-prism facet is capable of receiving substantially the same light flux, thereby forming a laser spot of substantially the same brightness. For example, a laser beam and its collimated beam typically have a gaussian transverse light intensity distribution; thus, the microprismatic optical element 30 may be designed such that, for example, the central surface 33a of the microprismatic surfaces 33 has a smaller area, while the microprismatic surfaces surrounding the central surface 33a have a larger area. By optimizing the area of each micro-prism face, the light intensity distribution between the individual points can be optimized, thereby adjusting the luminance uniformity between the individual generated laser points.
In an advantageous embodiment, the height differences of the plurality of microprismatic faces 33 are optimized such that microprismatic faces 33 abut each other in a substantially continuous manner, i.e. no jump steps are present between different microprismatic faces 33.
In an advantageous embodiment, the micro-prism optical element 30 has substantially the same profile dimensions as the beam diameter of the collimated beam. Here, the outline size refers to the outline size of both main surfaces of the microprism optical element 30. Thus, the beam splitting and the laser lattice generation based on the micro-prism optical element are facilitated, and the laser energy utilization efficiency is improved.
In an advantageous embodiment, the maximum profile dimension of the two main faces of the microprismatic optical element 30 is less than or equal to 5mm.
Next, a projection module 1A according to a second embodiment of the present invention will be described with reference to fig. 6 to 8. The projection module 1A according to the second embodiment has substantially the same structure as the projection module 1 according to the first embodiment, except that: the laser light source 10 in the projection module 1 is a single-point laser light source, and the laser light source 10' in the projection module 1A is a laser light source composed of a laser array.
In a preferred embodiment, the laser light source 10' may employ a VCSEL array in which a plurality of VCSEL lasers are arranged in an array. By way of example only and not limitation, fig. 7 shows a schematic view of an initial array LA of laser beams formed by an array of lasers, wherein each bright spot represents one laser beam emitted by one VCSEL laser in the array.
Referring back to fig. 6, different laser beams LB1, LB2 emitted by lasers at different positions on the laser light source 10' are collimated by the collimator device 20 to form corresponding collimated beams CB1, CB2 with different angles. The plurality of micro-prism facets 33 of the micro-prism optical element 30 split each of the collimated light beams CB1, CB2. Since the collimated light beams CB1, CB2 are incident on the micro-prism optical element 30 at different angles corresponding to different positions on the laser light source 10', the angles at which the micro-prism optical element 30 projects the split light beams BM11, BM12, BM13 split by the collimated light beam CB1 are different from the angles at which the split light beams BM21, BM22, BM23 split by the collimated light beam CB2 are projected according to the law of refraction of optics, thereby obtaining different points in the laser lattice.
In this way, if the laser light source 10' emits m laser light beams, the plurality of micro-prism faces 33 of the micro-prism optical element 30 have n inclination angles different from each other, and in an ideal case (all the micro-prism faces are irradiated with the collimated laser light beams), the plurality of micro-prism faces 33 split the beam to project a laser lattice of m×n laser spots.
Fig. 8 schematically shows an example diagram of a laser lattice obtained by using the projection module 1A shown in fig. 6. In this example, a laser light source 10' that produces an initial array of laser beams as shown in fig. 7 is employed in the projection module 1A, and a microprism optical element 30 (e.g., as shown in fig. 2) that is capable of projecting a laser lattice as shown in fig. 5 for a single laser light source is employed. As shown in fig. 8, the laser array obtained by the projection module 1A is a matrix obtained by arranging the initial array LA of laser beams generated by the laser light source 10' shown in fig. 7 according to the positions of the points in the matrix shown in fig. 5 (the boundary positions of the subsets of the matrix corresponding to the initial array are marked by four vertical and horizontal dashed lines in fig. 8). In other words, if the laser lattice formed by splitting and projecting a single laser beam by the plurality of micro-prism faces 33 is a single-point beam splitting lattice, the laser lattice projected by splitting a plurality of collimated beams corresponding to the initial array of laser beams by the plurality of micro-prism faces 33 has an array structure formed by arranging the initial lattice LA in accordance with the positions of the points in the single-point beam splitting lattice.
Laser arrays, such as VCSEL arrays, have been well established techniques to provide an initial lattice of closely spaced laser beams. However, the laser array directly provides a laser beam initial lattice with a small two-dimensional size that cannot be directly applied to, for example, structured light three-dimensional detection, especially long-range, large-size detection. According to the second embodiment of the invention, the advantages of refraction beam splitting and divergent projection of the micro-prism optical element can be exerted by combining and utilizing the array type laser light source, so that a large and/or dense laser lattice is obtained, the light utilization efficiency is improved, and the noise is reduced.
Next, a projection module 1B according to a third embodiment of the present invention is described with reference to fig. 9 to 11. The projection module 1B according to the third embodiment has substantially the same structure as the projection module 1 according to the first embodiment, except that: the micro-prism optical element 30' in the projection module 1B includes a plurality of micro-prism units 30A (see fig. 10), each micro-prism unit 30A including a plurality of micro-prism faces having different inclination angles; in contrast, the microprismatic optics 30 of the projection module 1 may be considered to comprise only a single microprismatic unit, or a microprismatic surface having only a single period.
For better understanding, fig. 10 shows one example of a microprismatic optical element 30' according to an embodiment of the invention. In the example shown in fig. 10, each of the micro prism units 30A of the micro prism optical element 30' may have, for example, the same structure as the plurality of micro prism faces 33 of the micro prism optical element 30 in the projection module 1, but be downsized so as to array a plurality of micro prism units 30A. Also, in the example shown in fig. 10, several microprism units 30A have the same structure and size and are periodically arranged.
Fig. 11 is a diagram showing an example of a laser array obtained by using the projection module 1B shown in fig. 9. In this example, a laser light source 10 of a single laser is employed in the projection module 1B, and the configuration of the micro prism face of each micro prism unit 30A in the micro prism optical element 30 'is the same as in the numerical example of the micro prism optical element 30 described above in connection with fig. 2, except that the micro prism unit 30A is downsized with respect to the micro prism optical element 30 so that a plurality of micro prism units 30A can be arranged in the micro prism optical element 30'. As shown in fig. 11, the array of laser lattices obtained by the projection module 1B corresponds to different inclination angles of the micro prism face 33 of each micro prism unit 30A in the micro prism optical element 30', irrespective of the number of micro prism units 30A.
The inventors propose to construct a micro-prism optical element 30' comprising several micro-prism units 30A because of the findings: the light intensity distribution of the incident light (collimated light beam CB) of the micro-prism optical element is generally uneven, and if the inclination angles of the plurality of micro-prism faces are different from each other, the unevenness of the incident light intensity may significantly affect the spot brightness uniformity of the obtained laser lattice. For this reason, the inventors proposed to form a plurality of microprism units for realizing different predetermined projection angles, and to reduce and closely arrange the microprism units, which corresponds to splitting light of respective areas in an incident light beam by each microprism unit, and finally converging split light beams projected by microprism faces having the same inclination angle in the microprism units, to form a common one spot. In other words, each spot in the laser spot array contributes to the light energy from the respective areas of the collimated beam CB where the light intensities are different, so each spot should ideally be uniform in brightness.
Fig. 12 shows a projection module 1C according to a fourth embodiment of the present invention. The projection module 1C according to the fourth embodiment has substantially the same structure as the projection module 1B according to the third embodiment, except that: the laser light source 10 in the projection module 1B is a single-point laser light source, and the laser light source 10' in the projection module 1C is a laser light source composed of a laser array.
As shown in fig. 12, different laser beams LB1 and LB2 emitted by lasers at different positions on the laser light source 10' are collimated by the collimator device 20 to form corresponding collimated beams CB1 and CB2 with different angles. The plurality of micro-prism facets 33 in the plurality of micro-prism units 30A of the micro-prism optical element 30' split each of the collimated light beams CB1, CB2. Since the collimated light beams CB1, CB2 are incident on the micro-prism optical element 30' at different angles corresponding to different positions on the laser light source 10', the angle at which the micro-prism optical element 30' projects the split light beams BM11', BM12', BM13' split by the collimated light beam CB1 is different from the angle at which the split light beams BM21', BM22', BM23' split by the collimated light beam CB2 are projected according to the law of refraction of optics, thereby obtaining different points in the laser lattice.
The laser lattice obtained by the projection module 1C is similar to the laser lattice obtained by the projection module 1A shown in fig. 8, and is not shown in the drawing. Briefly, the laser light source 10' generates a laser beam initial array LA, and if a laser lattice formed by splitting and projecting a single laser beam by a plurality of micro prism faces 33 of the micro prism optical element 30' is a single-point split lattice (see, for example, the array of fig. 11), the laser lattice projected by splitting a plurality of collimated beams corresponding to the laser beam initial array by the plurality of micro prism faces 33 of the micro prism optical element 30' has an array structure formed by arranging the initial lattice LA in accordance with the positions of the points in the single-point split lattice.
The projection module according to the third and fourth embodiments of the present invention is described above with reference to the example of the micro-prism optical element 30' shown in fig. 10. It should be understood that the projection module and the micro-prism optical element according to the embodiment of the present invention are not limited to the case where the respective micro-prism units 30A shown in fig. 10 have the same structure, the same size, and are periodically arranged. According to some embodiments of the present invention, each microprism unit 30A may also have a different structure and/or size. According to some embodiments of the invention, the individual microprismatic units 30A may also be arranged non-periodically.
Two modifications according to the micro-prism optical element will be described below with reference to fig. 13 to 15.
Fig. 13 shows a modification of the microprismatic optical element of fig. 10.
In fig. 13, only the microprism units 30A are represented by rectangular boxes for clarity and brevity, but it should be understood that each microprism unit 30A includes a plurality of microprism faces of different inclination angles; it should also be appreciated that microprismatic cells 30A are not limited to having a rectangular outline, but may be any suitable cell shape, such as triangular or hexagonal.
As shown in fig. 13, the micro-prism optical element 30″ according to this modification includes a plurality of micro-prism units 30A, and these micro-prism units 30A are non-periodically arranged and may have different sizes. This is advantageous in suppressing or eliminating interference/diffraction noise introduced due to the periodicity of the microprismatic face structure. Preferably, these microprism units 30A may have the same configuration. "configuration" herein refers to the number, position, and tilt angle of the micro-prism facets.
It should be understood that when the micro prism optical element 30″ according to the embodiment of the present invention is applied to, for example, the projection module 1B according to the third embodiment of the present invention and the projection module 1C according to the fourth embodiment of the present invention, the array of the laser light lattice to be projected is not changed. Furthermore, the stitching between the rectangular boxes of different sizes in fig. 13 is illustrative only, and one skilled in the art can readily appreciate that the non-periodically arranged differently sized microprismatic units 30A should stitch tightly one another to fill the entire light receiving area of the microprismatic optical element.
Fig. 14 shows a modification of the micro-prism optical element shown in fig. 2, and fig. 15 shows an example diagram of a laser lattice obtained by using the micro-prism optical element shown in fig. 14.
The plurality of microprismatic faces of the microprismatic optical element 30' "shown in fig. 14 have a rotationally symmetrical structure, and the central face 33a is parallel to the other main face, and the plurality of microprismatic faces 33 around the central face 33a are configured to have the same tilt angle with respect to the other main face (only the magnitude of the tilt angle is considered, regardless of the tilt orientation). The microprism optical element 30' "splits the incident light beam into a plurality of light beams arranged in a circular ring shape, resulting in a laser lattice as shown in fig. 15.
It should be understood that the structures of the microprismatic optical elements shown in fig. 2 and 14 are only exemplary, and the microprismatic surfaces of the microprismatic optical elements or the microprismatic surfaces in the microprismatic units thereof according to the embodiments of the present invention are not limited to forming rectangular arrays or circular ring-shaped lattices, and the arrays are not limited to periodic or regular arrays. According to some embodiments of the invention, the projection module and the microprism optical element may be configured to project, for example, laser speckle.
The above description is only illustrative of the preferred embodiments of the present application and of the principles of the technology employed. It will be appreciated by persons skilled in the art that the scope of the application referred to in the present application is not limited to the specific combinations of the technical features described above, but also covers other technical features formed by any combination of the technical features described above or their equivalents without departing from the inventive concept. Such as the above-mentioned features and the technical features disclosed in the present application (but not limited to) having similar functions are replaced with each other.
Claims (9)
1. A projection module for implementing a laser lattice, comprising:
A laser light source that emits one or more laser beams;
A collimating device that receives the one or more laser beams and collimates to form a substantially collimated one or more collimated beams; and
A microprism optical element having two principal faces for light to enter and exit, the two principal faces being opposed to each other, wherein at least one principal face includes a plurality of microprism faces having different angles of inclination, wherein the microprism optical element receives the one or more collimated light beams, splits the one or more collimated light beams by refraction of the plurality of microprisms by the plurality of microprisms, and causes split light beams resulting from splitting of the same collimated light beam to be projected along a plurality of different predetermined projection angles to obtain a laser lattice, wherein the split light beams projected by the plurality of microprism faces along the different predetermined projection angles respectively correspond to different points in the laser lattice, and the split light beams projected along the same predetermined projection angle correspond to the same point in the laser lattice.
2. The projection module of claim 1, wherein the microprismatic optical element has a profile dimension substantially the same as a beam diameter of the collimated beam.
3. The projection module of claim 1, wherein the plurality of microprismatic faces have mutually different tilt angles and the plurality of microprismatic faces have light receiving areas adapted to the lateral light intensity distribution of the collimated light beam such that each microprismatic face is capable of receiving substantially the same light flux.
4. The projection module of claim 1, wherein the laser light source comprises a laser array for emitting a plurality of laser beams; the collimating device receives the plurality of laser beams and collimates the plurality of laser beams to form a plurality of corresponding collimated beams; and the plurality of micro-prism facets of the micro-prism optical element split each of the plurality of collimated light beams.
5. The projection module of claim 4, wherein the plurality of laser beams emitted by the laser array form an initial lattice, and the laser lattice projected by the plurality of microprisms splitting the plurality of collimated beams has an array structure formed by arranging the initial lattice according to the positions of the points in the single-point beam splitting lattice assuming that the laser lattice formed by the plurality of microprisms splitting the single laser beam is the single-point beam splitting lattice.
6. The projection module of claim 4, wherein the laser light source emits m laser beams, the plurality of micro-prism surfaces of the micro-prism optical element have n different inclination angles from each other, and the plurality of micro-prism surfaces split the beam to project a laser lattice of m x n laser spots.
7. The projection module of any of claims 4-6, wherein the laser light source is a vertical cavity surface emitting laser.
8. The projection module of claim 1, wherein the plurality of microprismatic faces includes at least one central plane parallel to the other major face.
9. The projection module of claim 8, wherein the microprismatic faces around the central plane are symmetrically arranged with respect to the central plane.
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| CN202011409470.5A CN112505983B (en) | 2020-12-03 | 2020-12-03 | Microprism optical element for realizing laser dot matrix and projection module |
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| CN113625462B (en) * | 2021-09-13 | 2023-01-06 | 江西欧迈斯微电子有限公司 | Diffractive optical element, projection module, and electronic apparatus |
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| JP4098951B2 (en) * | 2000-09-20 | 2008-06-11 | ペンタックス株式会社 | Light source device for optical head |
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| TW201202123A (en) * | 2010-07-06 | 2012-01-16 | Hirose Tech Co Ltd | Manufacturing equipment of nano-scale structure array and production method |
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| WO2014004228A1 (en) * | 2012-06-27 | 2014-01-03 | 3M Innovative Properties Company | Optical component array |
| CN114904152A (en) * | 2020-07-31 | 2022-08-16 | 西安炬光科技股份有限公司 | Laser dot matrix system and laser dot matrix therapeutic instrument |
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| JPH10197826A (en) * | 1997-01-10 | 1998-07-31 | Asahi Optical Co Ltd | Beam shaping optical system |
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| CN114895505A (en) * | 2020-12-03 | 2022-08-12 | 嘉兴驭光光电科技有限公司 | Projection module for realizing laser dot matrix |
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| CN114895505A (en) | 2022-08-12 |
| CN112505983A (en) | 2021-03-16 |
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