Close-range laser communication optical system with large alignment tolerance

Abstract

The invention relates to the technical field of wireless laser communication, in particular to a close-range laser communication optical system with large alignment tolerance, which comprises a transmitting optical subsystem and a receiving optical subsystem, and is characterized in that the transmitting optical subsystem comprises a light source part, a first collimating lens, a micro-lens array, a second collimating lens, an optical scattering element and a third collimating lens; the light source part emits a point light source, the point light source is collimated into a collimated light beam through the first collimating lens, the collimated light beam is split by the micro-lens array to generate sub-light beams, the sub-light beams are collected by the second collimating lens to be collimated and scattered into divergent light beams through the optical scattering element, and the divergent light beams are collimated and emitted by the third collimating lens to form collimated light beams. The receiving optical subsystem receives the collimated light beam to realize short-distance laser communication, and the system converts a point light source into an area light source through a microlens array light beam homogenizing device, thereby improving the exit pupil diameter of the light beam and the emission numerical aperture, increasing the alignment tolerance of the two ends, and reducing the alignment difficulty of wireless laser communication equipment.

Description

Technical Field

[0001] The invention relates to the technical field of wireless laser communication, and in particular to a short-distance laser communication optical system with a large alignment tolerance. Background Art

[0002] The short-range wireless laser communication terminal is divided into two ends, each of which contains one optical transmitter and one optical receiver. Communication can only begin after the two devices are aligned.

[0003] Existing short-range wireless laser communications usually use laser diodes or fiber-coupled lasers as the transmitting light source. The light source is approximately a point light source and is directly collimated by the optical system to become a small-diameter, small-divergence-angle light beam with high directivity. Therefore, the terminal needs to be installed on a servo mechanism or a manual two-dimensional pan-tilt platform to accurately adjust the direction to align with the other end, or the installation surface needs to be polished or raised according to the pitch angle required by the terminal to achieve alignment.

[0004] However, the alignment and installation process is cumbersome and time-consuming, and the alignment is difficult. At the same time, when the aligned terminal is working, the relative position and alignment angle of the two installation surfaces of the equipment cannot deviate or jitter significantly. When fluids or obstructions with a diameter smaller than the light aperture pass through the space between the two terminals, it will also cause drastic fluctuations in the received power, thereby affecting the communication effect. Summary of the invention

[0005] The purpose of the present invention is to provide a short-range laser communication optical system with a large alignment tolerance, aiming to solve the problems that existing short-range laser communication terminals require precise alignment before use, the alignment and installation process is cumbersome and time-consuming, and the alignment is difficult.

[0006] To achieve the above object, the present invention provides a short-distance laser communication optical system with a large alignment tolerance, comprising a transmitting optical subsystem and a receiving optical subsystem, wherein the transmitting optical subsystem comprises a light source, a first collimator, a microlens array, a second collimator, an optical scattering element and a third collimator;

[0007] The light source is used to emit a point light source toward the first collimating mirror;

[0008] The first collimator is used to collimate the point light source into a collimated light beam with a small diameter and a small divergence angle of Gaussian distribution;

[0009] The microlens array is used to split the divergent sub-beams of the collimated light beam;

[0010] The second collimator is used to collect and collimate the divergent sub-beams split by the microlens array;

[0011] The optical scattering element is used to scatter each sub-collimated light beam output by the second collimating mirror into a divergent light beam with a certain divergence angle;

[0012] The third collimating mirror is used to collimate and emit the divergent light beam to form a collimated light beam;

[0013] The receiving optical subsystem is used to receive the collimated light beam to achieve short-range laser communication.

[0014] Wherein, the receiving optical subsystem includes a receiving mirror group and a detector;

[0015] The receiving mirror assembly is used to receive the collimated light beam of the third collimating mirror;

[0016] The detector is used to convert the focused light beam signal into an electrical signal, and the electrical signal is processed by other subsequent functional modules to complete signal transmission.

[0017] Wherein, the light source is a laser diode or a coupling optical fiber.

[0018] Wherein, the size of the microlens array is larger than the diameter of the collimated light beam.

[0019] Wherein, the optical scattering element includes frosted glass and a diffuser.

[0020] The present invention provides a short-distance laser communication optical system with a large alignment tolerance. The light source emits a point light source to the first collimator, and the first collimator collimates the point light source into a collimated light beam with a small diameter and a small divergence angle of Gaussian distribution. The microlens array is used to split the sub-beams diverged from the collimated light beam. The second collimator collects the sub-beams split by the microlens array and collimates them to obtain sub-collimated light beams with a large diameter. The optical scattering element scatters each sub-collimated light beam output by the second collimator into a divergent light beam with a certain divergence angle. Since the sub-collimated light beams are incident at different angles, The optical scattering element, each object point in the central area of ​​the optical scattering element can be uniformly irradiated by each sub-collimated light beam with different incident angles, so the divergent light beam output by each object point in the central area of ​​the optical scattering element has a consistent "angle-power distribution" characteristic, the third collimator collimates and emits the divergent light beam output by the optical scattering element, each object point of the optical scattering element corresponds to a different emission angle to form a collimated emission light beam with a large diameter, the receiving optical subsystem receives the collimated emission light beam to realize short-range laser communication, wherein the first collimator is placed behind the light source, and the object of the first collimator is The microlens array is placed behind the first collimator, each sub-lens of the microlens array has a smaller "focal length-aperture ratio", the second collimator is placed behind the microlens array, the object-side focal plane of the second collimator coincides with the image-side focal plane of the microlens array, the parameter selection principle of the second collimator is that its "focal length-aperture ratio" value should be smaller than the "focal length-aperture ratio" value of the sub-lenses of the microlens array, the optical scattering element is placed behind the second collimator, the third collimator is placed behind the optical scattering element, and the third collimator The parameter selection principle is that its "radius-focal length ratio" value should not be less than the tangent value of the half-divergence angle of the scattered light beam (tanθ / 2). The system has a compact design structure and good uniformity of the transmitted light beam power distribution, which is conducive to application in practical engineering. The received light beam is a surface light source that emits light uniformly at multiple angles. Therefore, the terminal has a certain ability to resist obstruction when performing communication, has strong operability, and low implementation cost. It has good practical value for the rapid alignment of wireless laser communications in scenarios without servo alignment mechanisms, and solves the problem that existing short-range laser communication terminals require precise alignment before use, and the alignment and installation process is cumbersome and time-consuming. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] 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.

[0022] Figure 1 The invention provides a short-distance laser communication optical system with a large alignment tolerance.

[0023] In the figure: 1-transmitting optical subsystem, 2-receiving optical subsystem, 3-light source, 4-first collimating mirror, 5-microlens array, 6-second collimating mirror, 7-optical scattering element, 8-third collimating mirror, 9-receiving mirror group, 10-detector. DETAILED DESCRIPTION

[0024] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0025] See also Figure 1 The present invention provides a short-distance laser communication optical system with a large alignment tolerance, comprising a transmitting optical subsystem 1 and a receiving optical subsystem 2, wherein the transmitting optical subsystem 1 comprises a light source 3, a first collimator 4, a microlens array 5, a second collimator 6, an optical scattering element 7 and a third collimator 8;

[0026] The light source 3 is used to emit a point light source to the first collimator 4;

[0027] The first collimator 4 is used to collimate the point light source into a collimated light beam with a small diameter and a small divergence angle of Gaussian distribution;

[0028] The microlens array 5 is used to split the collimated light beam to generate sub-beams;

[0029] The second collimator 6 is used to collect and collimate the sub-beams split by the microlens array 5;

[0030] The optical scattering element 7 is used to scatter each sub-collimated light beam output by the second collimating lens 6 into a divergent light beam with a certain divergence angle;

[0031] The third collimator 8 is used to collimate and emit the divergent light beam to form a collimated light beam;

[0032] The receiving optical subsystem 2 is used to receive the collimated light beam to achieve short-range laser communication.

[0033] In an embodiment of the present invention, the light source component 3 emits a point light source to the first collimator 4, the first collimator 4 collimates the point light source into a collimated light beam with a small diameter and a small divergence angle of Gaussian distribution, the microlens array 5 is used to split the collimated light beam to generate sub-beams, the second collimator 6 collects the sub-beams split by the microlens array 5 and collimates them, the optical scattering element 7 scatters each sub-collimated light beam output by the second collimator 6 into a divergent light beam with a certain divergence angle θ, the third collimator 8 collimates and emits the divergent light beam to form a collimated light beam, and the receiving optical subsystem 2 receives the collimated light beam to realize short-range laser communication, wherein the first collimator 4 is placed behind the light source component 3, the object focus of the first collimator 4 coincides with the light-emitting surface of the light source component 3, the microlens array 5 is placed behind the first collimator 4, and the microlens array 5 has m*m sub-lenses, and the diameter of each sub-lens is d a , focal length is f a , the focal length-aperture ratio of the sub-lens f a / d a is not greater than 2, each sub-lens of the microlens array 5 has a smaller "focal length-aperture ratio", the second collimator 6 is placed behind the microlens array 5, the object-side focal plane of the second collimator 6 coincides with the image-side focal plane of the microlens array 5, and the parameter selection principle of the second collimator 6 is that its "focal length-aperture ratio" value f2 / d2 should be smaller than the "focal length-aperture ratio" value f2 / d2 of the sub-lenses of the microlens array 5. a / d a The diameter of the second collimator 6 is d2, the focal length is f2, and the output beam diameter of the second collimator 6 is d 2out Approximately:

[0034]

[0035] The optical scattering element 7 is placed behind the second collimator 6, and the third collimator 8 is placed behind the optical scattering element 7. The diameter of the third collimator 8 is d3, and the focal length is f3. The parameter selection principle of the third collimator 8 is that its "radius-focal length ratio" value d3 / 2f3 should not be less than the tangent value (tanθ / 2) of the half divergence angle of the scattered light beam. Since the collimated light beam emitted by the third collimator 8 is the final output light beam of the emitting optical system, its divergence angle can be approximately calculated as:

[0036]

[0037] The diameter of the final output beam at the light outlet (the third collimator 8)

[0038] Usually it can be achieved through parameter design out The diameter d3 of the third collimator 8 is basically covered, that is, full aperture emission is achieved, thereby having a large radial alignment tolerance, and a large θ can also be achieved through parameter design. out The value can usually reach more than 10°, that is, a large divergence angle emission is achieved, so that it has a large angular alignment tolerance; the system has a compact design structure and good uniformity of the emitted light beam power distribution, which is conducive to application in actual engineering, and the received incident light beam is emitted by a multi-angle uniform luminous surface light source transformed from a point light source. Therefore, the terminal has a certain ability to resist obstruction when performing communication, strong operability, low implementation cost, and good practical value for the rapid alignment of wireless laser communication in the scenario of servo-free alignment mechanism, which solves the problem that the existing short-range laser communication terminal needs precise alignment before use, and the alignment and installation process is cumbersome and time-consuming.

[0039] Furthermore, the receiving optical subsystem 2 includes a receiving lens group 9 and a detector 10;

[0040] The receiving lens group 9 is used to receive the collimated light beam of the third collimating lens 8;

[0041] The detector 10 is used to convert the focused light beam signal into an electrical signal, and the electrical signal is processed by other subsequent functional modules to complete signal transmission.

[0042] In the embodiment of the present invention, the receiving lens group 9 receives the collimated light beam of the third collimator 8. The receiving lens group 9 uses a receiving lens group with a large numerical aperture to receive the transmitted light beam at the opposite end. The receiving focal length of the receiving lens group 9 is f reci The detector 10 is a detector with a large photosensitive surface that meets the communication rate requirements, and the diameter of the photosensitive surface is d d The receiving mirror group 9 cooperates with the detector 10 to achieve a large receiving field of view, and the large receiving field of view enables the entire communication field of view to have a large alignment angle tolerance.

[0043] Furthermore, the light source 3 is a laser diode or a coupling optical fiber, and the size d of the microlens array 5 is m Greater than the collimated beam diameter d o The optical scattering element 7 includes frosted glass and a diffuser.

[0044] In the embodiment of the present invention, the optical scattering element 7 may be frosted glass, a diffuser, or other elements capable of achieving a light beam scattering effect. The optical scattering element 7 achieves a scattering effect on the sub-collimated light beam, and the size should be no less than the output d 2out , the size is usually in the order of millimeters.

[0045] What is disclosed above is only a preferred embodiment of a short-range laser communication optical system with a large alignment tolerance of the present invention. Of course, this cannot be used to limit the scope of rights of the present invention. Ordinary technicians in this field can understand that all or part of the processes of the above embodiments and equivalent changes made in accordance with the claims of the present invention are still within the scope of the invention.

Claims

1. A short-range laser communication optical system with large alignment tolerance, characterized in that ； It includes a transmitting optical subsystem and a receiving optical subsystem, wherein the transmitting optical subsystem includes a light source, a first collimating mirror, a microlens array, a second collimating mirror, an optical scattering element and a third collimating mirror; The light source is used to emit a point light source toward the first collimating mirror; The first collimator is used to collimate the point light source into a collimated light beam with a small diameter and a small divergence angle of Gaussian distribution; The microlens array is used to split the divergent sub-beams of the collimated light beam; The second collimator is used to collect the divergent sub-beams split by the microlens array and collimate each divergent sub-beam; The optical scattering element is used to scatter each sub-collimated light beam output by the second collimating mirror into a divergent light beam with a certain divergence angle; The third collimating mirror is used to collimate and emit the divergent light beam to form a collimated light beam; The receiving optical subsystem is used to receive the collimated light beam to achieve short-range laser communication.

2. The short-distance laser communication optical system with large alignment tolerance as claimed in claim 1, characterized in that ； The receiving optical subsystem includes a receiving mirror group and a detector; The receiving lens assembly is used to receive the collimated light beam from the third collimating lens and convert the collimated light beam into a focused light beam; The detector is used to convert the focused light beam signal into an electrical signal, and the electrical signal is processed by other subsequent functional modules to complete signal transmission.

3. The short-distance laser communication optical system with large alignment tolerance as claimed in claim 1, characterized in that ； The light source is a laser diode or a coupling optical fiber.

4. The short-distance laser communication optical system with large alignment tolerance as claimed in claim 1, characterized in that ； The size of the microlens array is larger than the diameter of the collimated light beam.

5. The short-distance laser communication optical system with large alignment tolerance as claimed in claim 1, characterized in that ； The optical scattering element includes frosted glass and a diffusion sheet.

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