1. An optical beam splitter comprising an array of microstructures disposed on a substrate, the array of microstructures comprising a plurality of microstructures, wherein: the microstructure is in a Bao cover shape, and the axis of the microstructure is parallel to the column direction of the microstructure array and is vertical to the row direction of the microstructure array; defining the row direction and the column direction of the microstructure array as an X direction and a Y direction respectively, and enabling the microstructure to meet at least one of the following conditions: A1/A2 is more than 0.4 and less than 0.7, B1/B2 is more than 0.4 and less than 0.7, and C1/C2 is more than 0.3 and less than 0.5;

a1 is the distance between the middle cover bottom of one microstructure and the top of the next cover bottom of the same column in the Y direction, A2 is the distance between the middle cover bottom of one microstructure and the middle cover bottom in the Y direction, B1 is the distance between the top ends of two sharp angles of the cover bottom of one microstructure in the X direction, B2 is the distance between the top end of one sharp angle of the cover bottom of one microstructure and the top end of the adjacent sharp angle of the cover bottom of the next microstructure in the same row in the X direction, C1 is the distance between the top of the cover bottom of one microstructure and the inflection point of the upper platform of the cover in the Y direction, and C2 is the distance between the inflection point of the upper platform of one microstructure and the top end of any sharp angle of the cover bottom in the Y direction.

2. The optical splitter of claim 1, wherein: the single beam of light is laser; and/or, the beam splitter is used for splitting a single beam of light into a plurality of beams of light of 3 × 7; and/or the wavelength of the single beam of light is 600-1000 nm.

3. The optical splitter of claim 1, wherein: the diffraction angles of the optical beam splitter in the X direction and the Y direction are respectively 6-12 degrees and 12-18 degrees.

4. The optical splitter of claim 1, wherein: the substrate and the microstructure are both made of transparent materials, and the microstructure comprises a protruding structure or a concave structure arranged on the surface of the substrate; and/or the height of the projection or the depth of the recess of the microstructure relative to the surface of the substrate is 400-1200 nm.

5. The optical splitter of claim 4, wherein: the microstructure is formed on the surface of the substrate at least by stamping or etching.

6. The optical splitter according to any one of claims 1 to 5, wherein: the material of the substrate and the microstructure comprises optical glass or optical resin.

7. Use of the optical beam splitter according to any one of claims 1 to 6 for time-of-flight or structured light based depth detection or three-dimensional detection.

8. An optical assembly comprising a light source and the optical beam splitter of any one of claims 1-6; the light beam splitter is used for splitting the light rays emitted by the light source.

9. The optical assembly of claim 8, wherein: the light source includes a laser.

10. Use of the optical assembly of any one of claims 8-9 in time-of-flight or structured light based depth detection or three-dimensional detection.

Background

Time of flight (ToF) technology is often used in depth detection or three-dimensional detection, and a direct Time of flight (dtoff) method is currently in the mainstream, and unlike a traditional ito (indirect Time of flight) method, which projects a surface area light spot, dtoff requires a dot matrix light spot, so as to calculate a Time difference between projection and reception of each speckle, and further calculate depth information. In order to implement a dToF-based depth sensing scheme, a Diffractive Optical Element (DOE) such as a beam splitter is generally required as a core device to perform diffraction replication on incident light by using a microstructure pattern thereof, so as to achieve a beam splitting effect. For this reason, efforts have been made to find high performance optical splitters. In recent years, manufacturers have proposed beam splitters capable of splitting a single beam into 3 × 3 multiple beams, but the beam splitting effect is still to be improved.

Disclosure of Invention

The present invention is directed to a beam splitter and an application thereof, which overcome the disadvantages of the prior art.

In order to achieve the purpose, the technical scheme adopted by the invention comprises the following steps:

one aspect of an embodiment of the present invention provides an optical beam splitter, including a microstructure array disposed on a substrate, the microstructure array including a plurality of microstructures; the microstructure is in a Bao-Gai shape, and the axis of the microstructure is parallel to the column direction of the microstructure array and is vertical to the row direction of the microstructure array; defining the row direction and the column direction of the microstructure array as an X direction and a Y direction respectively, and enabling the microstructure to meet at least one of the following conditions: 0.4 < A1/A2 < 0.7, 0.4 < B1/B2 < 0.7, 0.3 < C1/C2 < 0.5:

a1 is the distance between the middle cover bottom of one microstructure and the top of the next cover bottom of the same column in the Y direction, A2 is the distance between the middle cover bottom of one microstructure and the middle cover bottom in the Y direction, B1 is the distance between the top ends of two sharp angles of the cover bottom of one microstructure in the X direction, B2 is the distance between the top end of one sharp angle of the cover bottom of one microstructure and the top end of the adjacent sharp angle of the cover bottom of the next microstructure in the same row in the X direction, C1 is the distance between the top of the cover bottom of one microstructure and the inflection point of the upper platform of the cover in the Y direction, and C2 is the distance between the inflection point of the upper platform of one microstructure and the top end of any sharp angle of the cover bottom in the Y direction.

Further, the beam splitter is used for splitting the single beam of light into a plurality of beams of light of 3 × 7.

Further, the single beam of light is laser light. Preferably, the wavelength of the laser is 600-1000 nm.

Furthermore, the diffraction angles of the optical beam splitter in the X direction and the Y direction are respectively 6-12 degrees and 12-18 degrees.

Further, the substrate and the microstructure are both made of transparent materials, and the microstructure comprises a protruding structure or a recessed structure arranged on the surface of the substrate. Preferably, the height of the projection or the depth of the recess of the microstructure relative to the substrate surface is 400-1200 nm.

In some embodiments, the microstructures are formed on the surface of the substrate by at least stamping or etching.

Further, the material of the substrate and the microstructure includes, but is not limited to, optical glass or optical resin.

Another aspect of embodiments of the present invention also provides the use of the optical beam splitter in time-of-flight or structured light based depth detection or three-dimensional detection.

Another aspect of an embodiment of the present invention also provides an optical module including a light source and the optical beam splitter; the light beam splitter is used for splitting the light rays emitted by the light source.

In some embodiments, the light source comprises a laser.

Another aspect of embodiments of the invention also provides the use of the optical assembly in time-of-flight or structured light based depth detection or three-dimensional detection.

Compared with the prior art, the optical beam splitter provided by the embodiment of the invention can realize a uniform beam splitting effect of 3 × 7, can meet the requirements of various dot matrix projection schemes (including speckle structure light and dToF), and has the advantages of simple preparation process, suitability for large-scale production and wide application prospect.

Drawings

FIG. 1 is a schematic diagram of a microstructure array of an optical beam splitter in an embodiment of the present invention;

FIG. 2 is a test chart of the beam splitting effect of an optical splitter according to an embodiment of the present invention.

Detailed Description

The technical scheme of the invention is concretely explained in the following by combining the drawings and some embodiments. It is to be understood that the following detailed description is exemplary and is intended to provide further explanation of the invention as claimed. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

One embodiment of the present invention provides a light beam splitter, which includes a microstructure array disposed on a substrate, as shown in fig. 1, the microstructure array includes a plurality of microstructures, and the microstructures are in a shape of a diamond cover; and the column direction of the microstructure array is parallel to the axis of the microstructure, and the row direction of the microstructure array is vertical to the axis of the microstructure. The row direction and the column direction of the microstructure array are respectively defined as the X direction and the Y direction. Then, the microstructure satisfies the following conditions: 0.4 < A1/A2 < 0.7, 0.4 < B1/B2 < 0.7, 0.3 < C1/C2 < 0.5:

a1 is the distance between the middle cover bottom of one microstructure and the top of the next cover bottom of the same column in the Y direction, A2 is the distance between the middle cover bottom of one microstructure and the middle cover bottom in the Y direction, B1 is the distance between the top ends of two sharp angles of the cover bottom of one microstructure in the X direction, B2 is the distance between the top end of one sharp angle of the cover bottom of one microstructure and the top end of an adjacent sharp angle of the cover bottom of the next microstructure in the same row in the X direction, C1 is the distance between the top of the cover bottom of one microstructure and the inflection point of the upper platform of the cover in the Y direction, and C2 is the distance between the inflection point of the upper platform of one microstructure and the top end of any sharp angle of the cover bottom in the Y direction.

The single beam of light can be split into 3 x 7 multiple beams of light using the beam splitter of this embodiment.

Wherein the single beam of light is preferably laser light with a wavelength of 600-1000 nm.

Wherein, the diffraction angles of the optical beam splitter in the X direction and the Y direction are respectively 6-12 degrees and 12-18 degrees.

Wherein, the substrate and the microstructure are both made of transparent materials.

In some cases, the microstructure includes a concave structure disposed on the surface of the substrate, which may be a pattern structure formed on the surface of the substrate by stamping, etching, or the like.

In other cases, the microstructure may further include a protruding structure disposed on the surface of the substrate, which may also be formed on the surface of the substrate by stamping or etching, or may be formed by transferring a prefabricated microstructure array onto the surface of the substrate and fixing the microstructure array on the substrate by bonding with an optical adhesive or the like.

Wherein the height of the protrusion structure protruding from the substrate surface or the depth of the recess structure recessed from the substrate surface may be 400-1200 nm.

The material of the substrate and the microstructure includes, but is not limited to, optical glass, optical resin, optical glue, or other organic or inorganic optical materials.

Preferably, a pattern corresponding to the microstructure array is processed on the optical glass or resin or corresponding optical glue by stamping or etching, and the microstructure array is formed, so as to obtain the optical beam splitter.

In a specific embodiment, the optical beam splitter is formed by coating an optical adhesive layer on optical glass and then pressing a microstructure array on the optical adhesive layer by using an imprinting mold with a preset convex pattern structure. The optical adhesive layer can be formed by using a commercially available UV adhesive, the coating thickness can be 2-20mm, the size of each microstructure in the x direction is 3-8A, the size in the y direction is 4-11 μm, and the stamping depth is 400-1200 μm. Of course, the pattern structure on the imprinting mold may be replaced with a recessed pattern structure. Fig. 2 shows the test results of splitting the laser light emitted from the laser with a wavelength of 600nm to 1000nm by using one of the beam splitters, and it can be seen that the beam splitter can achieve uniform splitting of 3 × 7 laser light.

The optical splitter of the present embodiment can be applied to depth detection or three-dimensional detection based on time-of-flight or structured light.

Accordingly, the present embodiments provide an optical assembly comprising a light source and the optical beam splitter.

Further, the light source includes a laser, such as a Vertical Cavity Surface Emitting Laser (VCSEL), and the like, without being limited thereto.

Further, to meet the requirements of practical operation, other optical components, such as a collimating mirror, etc., may be disposed between the light source and the beam splitter.

The embodiment also provides a method for depth detection or three-dimensional detection based on flight time or structured light by using the optical assembly. The method may be carried out in a variety of ways known in the art.

It is to be understood that the above-described embodiments are part of the present invention, and not all embodiments. The detailed description of the embodiments of the present invention is not intended to limit the scope of the invention as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.