Beam splitters, optical components and their applications

Abstract

This invention discloses a beam splitter, an optical component, and their applications, comprising a microstructure array disposed on a substrate. The microstructure array includes multiple cylindrical microstructures, each with an axis perpendicular to the substrate surface. The height of each microstructure is h, where 670 nm ≤ h ≤ 730 nm; the diameter of each microstructure is d, where 110 nm ≤ d ≤ 200 nm or 210 nm ≤ d ≤ 310 nm. The beam splitter of this invention, through micro-nano optical design, arranges nanocylinders on the substrate surface to form a microstructure array, achieving integrated collimation and beam splitting functions. This reduces the number of optical elements, simplifies the optical component structure, improves the optical component performance, and is suitable for mass production and application.

Description

Technical Field

[0001] This invention relates to the field of optical technology, and more specifically, to a beam splitter, an optical assembly having the beam splitter, and its applications. Background Technology

[0002] Time-of-Flight (ToF) technology is frequently used in depth or 3D inspection. A current mainstream trend in ToF solutions is the use of speckle projectors to project concentrated laser speckles. Unlike traditional methods that project area-wide speckles, this method projects lattice-like speckles (see reference). Figure 1 As shown, the light source energy can be concentrated in a few speckles, which can avoid excessive energy dispersion and thus improve the detection range of the ToF system.

[0003] Current dot projection schemes (including speckle structured light and dToF) require the use of diffractive optical elements (DOEs). Their function is to use microstructure patterns to diffract and replicate incident light, thereby achieving the effect of beam splitting. In addition, a collimating lens is needed to achieve the speckle projection effect. Therefore, the current scheme requires an additional collimating lens, which increases the complexity and cost of the components.

[0004] Therefore, a new solution is needed to address this problem. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a beam splitter, an optical component and its application.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a beam splitter, comprising a microstructure array disposed on a substrate, the microstructure array comprising multiple microstructures, the microstructures being cylindrical, the axis of the cylinders being perpendicular to the surface of the substrate, the height of the microstructures being h, 670nm≤h≤730nm; the diameter of the microstructures being d, 110nm≤d≤200nm or 210nm≤d≤310nm.

[0007] The present invention is further configured such that the height of the microstructure is h = 700 nm.

[0008] The present invention is further configured such that at least two microstructures in the microstructure array have different diameters.

[0009] The present invention is further configured such that the array direction of the microstructure array is mutually orthogonal x-direction and y-direction, and the array period in both x-direction and y-direction is 380-420nm.

[0010] The present invention is further configured such that the array periods in the x and y directions are equal.

[0011] The present invention is further configured such that the substrate is optical glass or optical resin.

[0012] The present invention also provides an optical component, including a light source and a beam splitter as described above, wherein the light source is a single beam of light, and the beam splitter is used to split the single beam of light into multiple beams of light distributed in an array in the x and y directions.

[0013] The present invention is further configured such that the wavelength of the single beam of light is 600-1000nm.

[0014] The present invention is further configured such that the wavelength of the single beam of light is 940 nm.

[0015] The present invention also provides the application of the above-described optical components in depth detection or three-dimensional detection based on time-of-flight or structured light.

[0016] In summary, the present invention has the following beneficial effects:

[0017] In this solution, the beam splitter, in conjunction with a single-beam light source, can achieve speckle projection, possessing the optical effect of combining a diffractive optical element (DOE) with a collimating lens element in traditional optical components, with a diffraction efficiency >90%. This beam splitter, through micro-nano optical design, arranges nanocylinders on the substrate surface to form a microstructure array, enabling integrated collimation and beam splitting functions, reducing the number of optical elements, simplifying the structure of optical components, improving the performance of optical components, and making it suitable for mass production and application. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the current laser speckle projection.

[0019] Figure 2 This is a schematic diagram of the microstructure array of a beam splitter in this embodiment;

[0020] Figure 3 This is a cross-sectional view of a microstructure array of a beam splitter in this embodiment;

[0021] Figure 4 This shows the correspondence between the diameter of the microstructure, the phase of the optical field, and the transmittance in this embodiment.

[0022] Figure reference numerals: substrate 1; microstructure array 2; microstructure 21. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] This embodiment discloses a beam splitter, referring to... Figure 2 , Figure 3 As shown, the system includes a substrate 1 and a microstructure array 2 disposed on the substrate. The microstructure array 2 includes multiple microstructures 21, each of which is cylindrical with its axis perpendicular to the substrate surface. Furthermore, the microstructures 21 are distributed in an array configuration. The parameters of each microstructure 21 are as follows: the height of the microstructure 21 is h, where 670 nm ≤ h ≤ 730 nm; the diameter of the microstructure 21 is d, where 110 nm ≤ d ≤ 200 nm or 210 nm ≤ d ≤ 310 nm.

[0025] In microstructure array 2, the array directions are mutually orthogonal x and y directions. The array period range in both the x and y directions is 380–420 nm.

[0026] Preferably, in the microstructure array 2, the height of the microstructure 21 is h = 700 nm, the array period in the x and y directions is equal, and the period is p, forming a square array distribution.

[0027] Reference Figure 4 As shown, cylindrical microstructures 21 with different diameters will form corresponding phases and transmittances. The phase has been normalized using 2*pi and can be adjusted according to the projection effect as needed. Regarding transmittance, when the diameter of microstructure 21 is in the range of 200–210 nm, a resonance peak appears, and the transmittance drops significantly; therefore, parameters for microstructure 21 in this range are not used. When the diameter of microstructure 21 is in the ranges of 110–200 nm and 210–300 nm, the transmittance performance is good, with a transmittance >80%, and it can cover the phase space adjustment from 0 to 2*pi.

[0028] Preferably, the transmittance is better when the diameter of the microstructure 21 is in the range of 110-190 and 220-300 nm, with a transmittance of >90%. Therefore, the diameter parameter of the microstructure 21 is preferably in this range.

[0029] In this embodiment, the beam splitter can split a single beam of light into multiple beams, and the projection pattern of the multiple beams can be specifically set as needed, for example, forming a 3×5 multiple beam. The diameters of the microstructures 21 in the microstructure array 2 vary, and the diameter of each microstructure 21 is specifically set according to the projection requirements. The specific distribution pattern of the diameters of each microstructure 21 can be adjusted according to the simulation parameters.

[0030] In this embodiment, the beam splitter is used in conjunction with a single-beam light source. For example, the single-beam light source can be a vertical-cavity surface-emitting laser (VCSEL), and the wavelength of the single beam is 600-1000 nm. Preferably, the wavelength of the single beam is 940 nm.

[0031] The beam splitter in this embodiment uses optical glass or optical resin as its substrate. Through micro-nano optical design, nanocylinders are arranged on the substrate surface to form a microstructure array 2, enabling integrated collimation and beam splitting functions. Using semiconductor processes on a pure silicon wafer, photolithography and etching are combined to fabricate micro-nano structures that meet the aforementioned parameter requirements, forming the required microstructure array 2, resulting in an optical element with microstructure array 2. This beam splitter can be used without a diffractive optical element (DOE) and can directly cooperate with a vertical-cavity surface-emitting laser (VCSEL) to directly achieve integrated collimation and beam splitting functions, reducing the number of optical elements and achieving structural simplification and cost control.

[0032] This embodiment also discloses an optical component, including a beam splitter and a vertical cavity surface-emitting laser (VCSEL light source) as described in the above embodiment. The beam splitter can split the single beam of light generated by the vertical cavity surface-emitting laser (VCSEL light source) into multiple beams of light distributed in an array in the x and y directions, for example, forming a 3×5 multiple beam of light.

[0033] This embodiment also discloses a method for depth detection or 3D detection based on time-of-flight or structured light using the optical components described in the above embodiments. This method can be implemented in various ways known in the art.

[0034] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiment. All technical solutions based on the concept of the present invention are within the scope of protection of the present invention. It should be noted that for those skilled in the art, various improvements and modifications that do not depart from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A beam splitter, characterized in that, The invention includes a microstructure array disposed on a substrate, the microstructure array comprising multiple microstructures, each microstructure being cylindrical with its axis perpendicular to the substrate surface, the height of the microstructure being h, where 670nm≤h≤730nm; and the diameter of the microstructure being d, where d is in the range of 110~190 and 220~300nm. The array of the microstructure array has mutually orthogonal x and y directions, and the array period in both x and y directions is 380~420nm; the array periods in x and y directions are equal. A single beam of light is used as the light source, with a wavelength of 600-1000nm; the light transmittance is >90%, covering 0~2 The phase space of pi.

2. A beam splitter according to claim 1, characterized in that, The height of the microstructure is h = 700 nm.

3. A beam splitter according to claim 1, characterized in that, At least two microstructures in the microstructure array have different diameters.

4. A beam splitter according to claim 1, characterized in that, The substrate is optical glass or optical resin.

5. An optical component, characterized in that, The device includes a light source and a beam splitter as described in any one of claims 1-4, wherein the light source is a single beam of light, and the beam splitter is used to split the single beam of light into multiple beams of light distributed in an array in the x and y directions.

6. The optical component according to claim 5, characterized in that, The wavelength of the single beam of light is 940 nm.

7. Use of the optical component as described in claim 5 in depth detection or three-dimensional detection based on time-of-flight or structured light.

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