Self-adaptive light beam gathering device
Through the beam gathering device of aspherical microlens array, Fresnel lens and cone fiber components, the problem of difficult beams with large divergence angles and deviating from the optical axis is solved, and efficient detection of the beam is achieved.
Patent Information
- Application Number
- CN202422235339.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-10
- Publication Date
- 2025-07-08
- Estimated Expiration
- 2034-09-10
AI Technical Summary
In the prior art, laser light with a large divergence angle and beams that deviate from the optical axis are difficult to be effectively collected by the photodetector, resulting in inaccurate detection results or inability to detect.
Using a combination of an aspherical microlens array, a Fresnel lens, a cone fiber and a lens assembly, the beam with a large divergence angle and a deviation from the optical axis is focused and collected into the photodetector through optical path adjustment.
The beam with a large divergence angle and a deviation from the optical axis is realized to be received by the photodetector to the maximum extent, improving the accuracy of detection and light energy utilization.
Smart Images
Figure CN223078541U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of optics, and more specifically, particularly relates to an adaptive beam focusing device. Background Art
[0002] Semiconductor lasers, all-solid-state lasers, fiber lasers, etc. have the advantages of high reliability, small size, low cost, high efficiency, etc., and are widely used in the fields of medicine, communication, material processing, measuring instruments, etc. Therefore, it is particularly important to accurately measure the optical properties such as the spectrum, power, frequency spectrum, time series, etc. of the laser output by various lasers.
[0003] Generally, the laser directly output by a semiconductor laser has a large divergence angle and poor beam quality. Compared with semiconductor lasers, the lasers output by all-solid-state lasers and fiber lasers have a smaller divergence angle and higher beam quality. When it comes to detecting the optical properties such as the time series and power spectrum of the laser, it is usually necessary to collect the laser to be detected into a photodetector for subsequent detection. For a laser with a small divergence angle and coinciding with the optical axis, it is relatively easy to collect it into the photodetector, and the detection result is relatively accurate. However, for a laser with a large divergence angle, when directly collecting it into the photodetector, limited by the size of the photodetector (1 - 2 mm), only a very small part of the light energy is incident on the photodetector, which is not conducive to subsequent detection; for a laser with a small divergence angle but deviated from the optical axis, it is very likely that it will not be incident on the photodetector at all after transmission, resulting in complete inability to detect.
[0004] In addition, due to its good light-emitting performance, LED has been highly regarded in lighting applications. When applied to lighting, we need to measure the intensity, frequency, or other optical characteristics of its light. However, the beam emitted by the LED has a large divergence angle and is deviated from the optical axis, etc. If the beam is directly collected into the photodetector, the photodetector may only receive a small part or even no light energy, which is not conducive to subsequent detection.
[0005] Based on this, we propose an adaptive beam focusing system that can focus a beam with a large divergence angle and deviated from the optical axis so that it can be received by the photodetector to the greatest extent. Summary of the Utility Model
[0006] The purpose of the utility model is to provide an adaptive beam focusing device to solve the problems existing in the prior art. By setting an aspherical microlens array, a Fresnel lens, a tapered optical fiber, and a lens assembly, a beam with a large divergence angle and deviated from the optical axis is focused and collected into a photoreceiver.
[0007] To achieve the above object, the present utility model provides the following solutions: The present utility model provides an adaptive beam focusing device, including: an aspherical microlens array, the central axis of the aspherical microlens array coincides with the optical axis, and the aspherical microlens array is used to receive the non-parallel beam emitted by the light source; a Fresnel lens, the Fresnel lens is located on the right side of the aspherical microlens array and is centered with the aspherical microlens array, and is used to receive the parallel beam transmitted by the aspherical microlens array; a tapered optical fiber, the tapered optical fiber is located on the right side of the Fresnel lens and is centered with the Fresnel lens, and the tapered optical fiber is used to receive the beam transmitted by the Fresnel lens; a lens assembly, the lens assembly is located on the right side of the tapered optical fiber and is centered with the tapered optical fiber, and the lens assembly is used to receive the beam output by the tapered optical fiber and transmit and focus the beam onto the photodetector.
[0008] Further, the aspherical microlens array is placed on a lens holder, and the aspherical microlens array is composed of a plurality of aspherical microlenses.
[0009] Further, the central axis of the Fresnel lens coincides with the optical axis, the Fresnel lens is placed on a lens holder, and the Fresnel lens transmits and converges the beam into the tapered optical fiber.
[0010] Further, the central axis of the tapered optical fiber coincides with the optical axis, the tapered optical fiber is fixed on the lens holder after being clamped by a fiber holder, and the tapered optical fiber transmits and outputs the beam into the lens assembly.
[0011] Further, the lens assembly is placed on a lens holder, and the lens assembly includes: a concave lens, the central axis of the concave lens coincides with the optical axis, and the concave lens is located on the right side of the tapered optical fiber; a first convex lens, the central axis of the first convex lens coincides with the optical axis, and the first convex lens is located on the right side of the concave lens; a second convex lens, the central axis of the second convex lens coincides with the optical axis, and the photodetector is arranged on the right side of the second convex lens.
[0012] Further, the center of the photodetector coincides with the optical axis, and the photodetector is placed on an adjustable fixing frame.
[0013] Further, the light source is placed on a light source holder, the light source includes a first light source and a second light source, the first light source is located above the optical axis, and the second light source is located below the optical axis.
[0014] The present utility model discloses the following technical effects:
[0015] The light source emits a light beam onto the aspherical microlens array. After receiving the divergent light beam, the aspherical microlens array emits a parallel light beam onto the Fresnel lens. After receiving the parallel light beam, the Fresnel lens converges the light beam into the tapered optical fiber. The tapered optical fiber receives and transmits the light beam to the lens assembly, and the lens assembly homogenizes and expands the light beam so as to subsequently focus it into a smaller-sized light spot, facilitating the complete reception of the light beam by the photodetector. This device can collect and focus the light beam with a large divergence angle and off-axis into the photodetector, enabling the photodetector to receive the light energy to the greatest extent for subsequent detection, and it has good application prospects and commercial value in the fields of industry, medicine, scientific research, military, etc. Brief Description of the Drawings
[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.
[0017] Figure 1 It is a schematic diagram of the overall structure of the present invention;
[0018] Figure 2 It is a schematic diagram of the structure of the aspherical microlens array in the present invention;
[0019] Figure 3 It is a schematic diagram of the structure in which the photodetector completely receives the light beam in the present invention;
[0020] Figure 4 It is a schematic diagram of the structure in which the photodetector receives the light beam in the prior art;
[0021] Figure 5 It is a schematic diagram of the structure in which the photodetector just cannot receive the light beam in the prior art;
[0022] Figure 6 Applied to the present invention Figure 5 It is a schematic diagram of the structure in which the photodetector receives the light beam when
[0023] Among them, 1. Light source; 101. First light source; 102. Second light source; 2. Aspherical microlens array; 3. Fresnel lens; 4. Tapered optical fiber; 5. Concave lens; 6. First convex lens; 7. Second convex lens; 8. Photodetector; 9. Optical axis. Detailed Embodiments
[0024] The following will clearly and completely describe the technical solutions in the embodiments of the present utility model in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.
[0025] To make the above objects, features, and advantages of the present utility model more obvious and understandable, the present utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments.
[0026] As Figures 1 - 6 shown, the present utility model provides an adaptive beam focusing device, which includes a light source 1, an aspherical microlens array 2, a Fresnel lens 3, a tapered fiber 4, a lens assembly, and a photodetector 8. The lens assembly includes a concave lens 5, a first convex lens 6, and a second convex lens 7. Among them, the light source 1, the aspherical microlens array 2, the Fresnel lens 3, the tapered fiber 4, the concave lens 5, the first convex lens 6, the second convex lens 7, and the photodetector 8 are arranged in sequence from left to right along the optical axis 9, and the central axes of the aspherical microlens array 2, the Fresnel lens 3, the tapered fiber 4, the concave lens 5, the first convex lens 6, the second convex lens 7, and the photodetector 8 coincide with the optical axis 9, so that the centers of the aspherical microlens array 2, the Fresnel lens 3, the tapered fiber 4, the concave lens 5, the first convex lens 6, the second convex lens 7, and the photodetector 8 are aligned with each other.
[0027] The light source 1 is placed on a light source fixed bracket, and the aspherical microlens array 2, the Fresnel lens 3, the tapered fiber 4, the concave lens 5, the first convex lens 6, and the second convex lens 7 are respectively placed on lens brackets for fixation. The tapered fiber 4 is clamped by a fiber holder and then placed on a lens bracket for fixation. The photodetector 8 is placed on an adjustable fixed bracket for fixation. By adjusting the height of the bracket, it is ensured that the centers of the aspherical microlens array 2, the Fresnel lens 3, the tapered fiber 4, the concave lens 5, the first convex lens 6, the second convex lens 7, and the photodetector 8 coincide with the optical axis 9. Among them, the light source 1 fixed bracket, the lens brackets, the fiber holder, and the adjustable fixed bracket are all placed on an optical rail to ensure the collimation of the optical path.
[0028] The light source 1 is used to emit a beam. The beam is a non-parallel beam with a certain divergence angle, and the position of the light source 1 randomly deviates from the optical axis 9 within a certain range. In this embodiment, the position of the first light source 101 is offset above the optical axis 9, and the position of the second light source 102 is offset below the optical axis 9. In this embodiment, the light source 1 is an LED light source with a divergence angle of 120° and the wavelength of the emitted light is 360 - 830 nm. The horizontal distances between the first light source 101 and the second light source 102 and the aspherical microlens array 2 are set to 5 mm.
[0029] As shown Figure 2 in the figure, the aspherical microlens array 2 is composed of multiple aspherical microlenses, and both sides are coated with broadband high-transmission dielectric films at 360 - 830 nm. The light-transmitting cross-section is 25×25 mm 2 , which is used to receive the non-parallel light beam emitted by the light source 1 and transmit the non-parallel light beam to the Fresnel lens 3, and the transmitted light beam is close to a parallel light beam. The function of multiple aspherical microlenses is to transmit the light beams with different incident directions into light beams close to parallel light beams.
[0030] Both sides of the Fresnel lens 3 are coated with broadband high-transmission dielectric films at 360 - 830 nm, and the diameter is 25 mm. It is used to receive the parallel light beam transmitted by the aspherical microlens array 2 and transmit and converge the light beam into the tapered optical fiber 4.
[0031] The tapered optical fiber 4 is a multi-core tapered optical fiber 4, and both ends are coated with broadband high-transmission dielectric films at 360 - 830 nm. One end faces the Fresnel lens 3, and the other end faces the concave lens 5; the end of the tapered optical fiber 4 facing the Fresnel lens 3 is the incident end of the tapered optical fiber 4, and the diameter of the incident end is 15 mm. The end facing the concave lens 5 is the output end of the tapered optical fiber 4, and the diameter of the output end is 5 mm. The tapered optical fiber 4 is used to receive the light beam transmitted by the Fresnel lens 3 and transmit and output the light beam to the concave lens 5.
[0032] Both sides of the concave lens 5 are coated with broadband high-transmission dielectric films at 360 - 830 nm, the diameter is 5 mm, and the focal length is -20 mm. It is close to the output end of the tapered optical fiber 4 and is used to receive the light beam output by the tapered optical fiber 4 and diverge the light beam. The diverging light beam is transmitted to the first convex lens 6.
[0033] Both sides of the first convex lens 6 are coated with broadband high-transmission dielectric films at 360 - 830 nm, the diameter is 5 mm, and the focal length is 40 mm. It is placed 20 mm to the right of the concave lens 5 and is used to receive the light beam transmitted by the concave lens 5 and converge the light beam into a parallel light beam. The parallel light beam is transmitted to the second convex lens 7.
[0034] Both sides of the second convex lens 7 are coated with broadband high-transmission dielectric films at 360 - 830 nm, the diameter is 5 mm, and the focal length is 20 mm. It is placed 20 mm to the right of the convex lens and is used to receive the light beam transmitted by the first convex lens 6 and transmit and focus the light beam onto the photodetector 8.
[0035] The photodetector 8 is a silicon photodiode, the response wavelength range is 200 - 1100 nm, and the effective cross-section is 2×2 mm2. The photodetector 8 is placed at the focal length of the second convex lens 7, that is, 20 mm to the right of the second convex lens 7, and is used to receive the light beam transmitted by the second convex lens 7 and detect the performance of the light beam.
[0036] The concave lens 5 and the first convex lens 6 are used to homogenize and expand the light beam so that the second convex lens 7 can focus the light beam into a smaller spot.
[0037] In this embodiment, first, the first light source 101 and the second light source 102 emit light beams onto the aspherical microlens array 2, and the light beams are divergent light beams; second, the aspherical microlens array 2 receives and transmits the light beams onto the Fresnel lens 3, and the transmitted light beams are parallel light beams; further, the Fresnel lens 3 receives and transmits the light beams into the tapered optical fiber 4, and the transmitted light beams are convergent light beams; further, the tapered optical fiber 4 receives and transmits the light beams onto the concave lens 5, and the output light beams are divergent light beams; further, the concave lens 5 receives and transmits the light beams onto the first convex lens 6, and the transmitted light beams are divergent light beams; further, the first convex lens 6 receives and transmits the light beams onto the second convex lens 7, and the transmitted light beams are parallel light beams; further, the second convex lens 7 receives and transmits the light beams onto the photodetector 8, and the transmitted light beams are convergent light beams; further, the photodetector 8 receives and measures the light beams.
[0038] As Figure 3 shown, using this device enables the photodetector 8 to fully receive the light beam. The light source 1 is an LED light source that emits a light beam with a 120° divergence angle. Among them, the first light source 101 and the second light source 102 respectively represent two situations of the LED light source at different positions, that is, they represent that the position of the LED light source deviates from the optical axis 9. The horizontal distances between the first light source 101 and the second light source 102 and the aspherical microlens array 2 are set to 5 mm. When the first light source 101 deviates upward from the optical axis 9 by no more than 3.8 mm and the second light source 102 deviates downward from the optical axis 9 by no more than 3.8 mm, the light beam emitted by the light source 1 can be fully collected by the photodetector 8.
[0039] Figure 4 is a schematic structural diagram of the photodetector 8 receiving the light beam without using this device. Among them, the light source 1 is an LED light source that emits a light beam with a 120° divergence angle and does not deviate from the optical axis 9. The light source 1 and the photodetector 8 are coaxial, and the distance between them is set to 5 mm. After the light beam emitted by the light source 1 propagates 5 mm, the diameter of the light beam is about 17.4 mm, and the cross-section of the light beam is about S1 = 237.7 mm 2 . The effective cross-section S2 of the photodetector 8 for receiving the light beam emitted by the light source 1 is 4 mm 2 . Through estimation, it can be obtained that the reception rate of the photodetector 8 for the light beam emitted by the light source 1 is about η1 = S2 / S1 = 1.7%.
[0040] Figure 5It is a schematic structural diagram of the situation where the photodetector 8 just cannot receive the light beam when the device is not used. Among them, the positions of the first light source 101 and the second light source 102 deviate from the optical axis 9. The horizontal distance between the first light source 101 and the second light source 102 and the aspherical microlens array 2 is set to 5 mm. When the first light source 101 deviates upward from the optical axis by 99.7 mm and the second light source 102 deviates downward from the optical axis by 99.7 mm, the photodetector 8 just cannot collect the light beam.
[0041] Figure 6 It is on the basis of Figure 5 that, when the device is used, it is a schematic structural diagram of the photodetector 8 receiving the light beam. The light source 1 is an LED light source that emits a light beam with a divergence angle of 120°. Among them, the first light source 101 and the second light source 102 represent two situations of the LED light source at different positions, that is, they represent that the position of the LED light source may deviate from the optical axis 9. The horizontal distance between the first light source 101 and the second light source 102 and the aspherical microlens array 2 is set to 5 mm. The first light source 101 deviates upward from the optical axis by 99.7 mm, and the second light source 102 deviates downward from the optical axis by 99.7 mm. After the light beam emitted by the first light source 101 propagates 5 mm, the light beam diameter is about 8.7 mm, and the light beam cross-section is S3 = 237.7 mm 2 . The effective cross-section of the aspherical microlens array 2 receiving the light beam emitted by the first light source 101 is about S4 = 168.2 mm 2 . That is, all this part of the light can be transmitted to the photodetector 8 through the subsequent system and be received by the photodetector 8. The reception rate of the light beam emitted by the first light source 101 by the photodetector 8 is about η2 = S4 / S3 = 70.8%. Similarly, the reception rate of the light beam emitted by the second light source 102 by the photodetector 8 is also about η2 = S4 / S3 = 70.8%.
[0042] When the light source 1 deviates within a certain range, when using this device to collect the light beam, the light beam can be completely received. When the device is not used to collect the light beam, only 1.7% of the light is collected (as shown in Figure 3 and 4 ); when the light beam deviates from the optical axis 9 to a certain extent, that is, when the light beam cannot be received when the device is not used, using this device can receive 70.8% of the light energy (as shown in Figure 5 and 6 ).
[0043] In the description of the present utility model, it should be understood that the orientation or positional relationship indicated by the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present utility model, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present utility model.
[0044] The embodiments described above are only descriptions of the preferred modes of the present utility model, and do not limit the scope of the present utility model. Without departing from the design spirit of the present utility model, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present utility model shall fall within the protection scope determined by the claims of the present utility model.
Claims
1. An adaptive beam focusing device, characterized in that, Comprising: An aspherical microlens array (2), the central axis of the aspherical microlens array (2) coincides with the optical axis (9), and the aspherical microlens array (2) is used to receive the non-parallel light beam emitted by the light source (1); A Fresnel lens (3), the Fresnel lens (3) is located on the right side of the aspherical microlens array (2) and is centered with the aspherical microlens array (2), and is used to receive the parallel light beam transmitted by the aspherical microlens array (2); A tapered optical fiber (4), the tapered optical fiber (4) is located on the right side of the Fresnel lens (3) and is centered with the Fresnel lens (3), and the tapered optical fiber (4) is used to receive the light beam transmitted by the Fresnel lens (3); A lens assembly, the lens assembly is located on the right side of the tapered optical fiber (4) and is centered with the tapered optical fiber (4), and the lens assembly is used to receive the light beam output by the tapered optical fiber (4) and transmit and focus the light beam onto the photodetector (8).
2. The adaptive beam focusing device according to claim 1, wherein: The aspherical microlens array (2) is placed on a lens holder, and the aspherical microlens array (2) is composed of a plurality of aspherical microlenses.
3. The adaptive beam focusing device according to claim 1, wherein: The central axis of the Fresnel lens (3) coincides with the optical axis (9), the Fresnel lens (3) is placed on a lens holder, and the Fresnel lens (3) transmits and converges the light beam into the tapered optical fiber (4).
4. The adaptive beam focusing device according to claim 3, wherein: The central axis of the tapered optical fiber (4) coincides with the optical axis (9), the tapered optical fiber (4) is fixed on the lens holder after being clamped by a fiber holder, and the tapered optical fiber (4) transmits and outputs the light beam into the lens assembly.
5. The adaptive beam focusing device according to claim 4, wherein: The lens assembly is placed on a lens holder, and the lens assembly includes: A concave lens (5), the central axis of the concave lens (5) coincides with the optical axis (9), and the concave lens (5) is located on the right side of the tapered optical fiber (4); A first convex lens (6), the central axis of the first convex lens (6) coincides with the optical axis (9), and the first convex lens (6) is located on the right side of the concave lens (5); A second convex lens (7), the central axis of the second convex lens (7) coincides with the optical axis (9), and the photodetector (8) is arranged on the right side of the second convex lens (7).
6. The adaptive beam focusing device according to claim 5, wherein: The center of the photodetector (8) coincides with the optical axis (9), and the photodetector (8) is placed on an adjustable fixing frame.
7. The adaptive beam focusing device according to claim 1, wherein: The light source (1) is placed on a light source holder, the light source (1) includes a first light source (101) and a second light source (102), the first light source (101) is located above the optical axis (9), and the second light source (102) is located below the optical axis (9).