CN115752716A

CN115752716A - High-sensitivity optical signal detection optical-mechanical structure based on grating

Info

Publication number: CN115752716A
Application number: CN202211126008.3A
Authority: CN
Inventors: 宋文华; 朱宝龙; 李明君; 杨明
Original assignee: Nanjing Xuwei Intelligent Technology Co ltd
Current assignee: Nanjing Xuwei Intelligent Technology Co ltd
Priority date: 2022-09-16
Filing date: 2022-09-16
Publication date: 2023-03-07

Abstract

The invention relates to a design improvement for improving the detection sensitivity and accuracy of a photoelectric detector, in particular to a high-sensitivity optical signal detection optical-mechanical structure based on a grating, which has the characteristics of miniaturization, low cost and easy adjustment, and has a detection system capable of improving the sensitivity and the signal-to-noise ratio of a sensor and a scattered light collection unit capable of reducing the acquisition error; the optical path shaping device comprises a receiving system (111), an optical path shaping system (112) and an optical signal collecting system (113), wherein light beams enter the receiving system (111) after passing through the optical signal collecting system (113) and the optical path shaping system (112) in sequence, and the optical path shaping system (112) is characterized by comprising a second aspheric lens (5), an array scattering sheet (4) and a first aspheric lens (3) in sequence from the incident direction of optical signals; the optical signal collection system (113) adopts a plano-convex lens (6) and is arranged along the direction of an optical signal; the light path shaping system (112) further comprises a circular aperture diaphragm (8).

Description

High-sensitivity optical signal detection optical-mechanical structure based on grating

Technical Field

The invention relates to design improvement for improving the detection sensitivity and accuracy of a photoelectric detector, in particular to a grating-based high-sensitivity optical signal detection optical-mechanical structure.

Background

At present, high-precision optical technology is continuously developed, and the detection requirement on optics is always continuously improved in the experimental process. And detection of a tiny spot is difficult in areas such as laser radar detection. The array of detection pixels of the detector cannot be completely tiled and without voids. The problems of small signal missing, large deviation of the detected signal size and the like are caused, and the detection performance limited by a single pixel may have a threshold value, so that the detection result has a large error.

In order to improve accuracy, the conventional photoelectric detection equipment usually improves accuracy by methods such as improving a pixel value or increasing detection sensitivity of each pixel, and the like.

Therefore, the high-precision photoelectric detection structure in the prior art is expensive in price, low in utilization rate and more limited in use scenes.

Disclosure of Invention

The invention aims to provide a grating-based high-sensitivity optical signal detection optical-mechanical structure, which has the characteristics of miniaturization, low cost and easiness in adjustment, and has a detection system capable of improving the sensitivity and the signal-to-noise ratio of a sensor and a scattered light collection unit capable of reducing the acquisition error.

In order to achieve the purpose, the invention provides the following technical scheme: a high-sensitivity optical signal detection optical-mechanical structure based on a grating comprises a receiving system, a light path shaping system and a light signal collecting system, wherein light beams sequentially pass through the light signal collecting system and the light path shaping system and then enter the receiving system.

Preferably, the optical signal collection system adopts a plano-convex lens and is arranged along the direction of the optical signal.

Preferably, the receiving system comprises a photodetector, a grating and an extinction structure; the grating is positioned in the receiving direction of the photoelectric detector, and the extinction structure is arranged outside the grating and the photoelectric detector.

Preferably, the optical path shaping system further comprises a circular hole diaphragm, and the circular hole diaphragm is arranged between the grating and the first aspheric lens.

Preferably, the photodetector is embodied as a multi-pixel detection array.

Preferably, the extinction structure should achieve an absorption of the laser light of greater than 0.99.

Preferably, the optical grating can realize optical branching to form a spot lattice on the surface of the photoelectric detector.

Compared with the prior art, the invention has the beneficial effects that: the target light rays are emitted to the light signal collecting system from the outside, the energy density of the received scattered light signals is improved through the large plano-convex lens, and the signal-to-noise ratio and the sensitivity of the sensor are further improved. And the beam is respectively shaped by a second aspherical mirror, an array scattering sheet and a first aspherical mirror in the beam shaping system, collimation is realized as much as possible, smaller target light spots are obtained, the wave-front intensity distribution of the light beam is more uniform, and the resolution of the detector is improved. Stray light is eliminated through the circular hole diaphragm, and reflected stray light generated in the light shaping process is prevented.

The light spot size can be adjusted by only adjusting the two aspheric lenses back and forth, the homogenized and bundled light beam is split into a light spot lattice after passing through a grating in a receiving system, and the structure of the grating is determined according to the tiling interval of detection pixels of a target detector and the adjusted light spot size, so that the split light spot lattice can hit the center of the detector pixel as much as possible.

The extinction structure can prevent external stray light interference, and provides a black cavity environment, so that the optical background noise of the sensor is greatly reduced, and the signal-to-noise ratio model reception is improved. And converting the optical signal obtained after the optical signal is received into an electric signal and transmitting the electric signal to a subsequent photoelectric signal processing device for analysis.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a schematic diagram of a gas signal collection, shaping and detection apparatus of the present invention;

fig. 3 is a schematic view of the detection acquisition of the present invention.

Description of the drawings: 111. a receiving system; 112. an optical path shaping system; 113. an optical signal collection system; 1. a photodetector; 2. a grating; 3. a first aspherical lens; 4. an array diffuser; 5. a second aspherical lens; 6. a plano-convex lens; 7. a light extinction structure; 8. a circular hole diaphragm; 9. a light spot lattice; 10. a multi-pixel detection array; 11. photoelectric signal processing device.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. 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.

The grating-based high-sensitivity optical signal detection optical-mechanical structure redesigns an optical detection system and adopts an optical signal collection system capable of converging optical signals in order to improve the resolution, accuracy and stability of a precise optical detection sensor and reduce debugging difficulty.

The optical-mechanical structure shown in fig. 1 and fig. 2 mainly includes a receiving system 111; an optical path shaping system 112; an optical signal collection system 113; a high-precision photoelectric detector 1, a grating 2 and an extinction structure 7 are arranged in the receiving system 111; the optical path shaping system 112 comprises a circular aperture diaphragm 8, a first aspheric lens 3, an array diffuser 4 and a second aspheric lens 5 which are arranged behind the receiving system 111; the optical signal collection system 113 comprises a plano-convex lens 6 placed perpendicular to the beam direction.

The required received optical signal is collected, compressed and converged to the inlet of the optical path shaping system 112 by the plano-convex lens 6 in the optical signal collection system 113. After the light path of the light beam is adjusted by the second aspheric lens 5, the intensity of the laser wave front is uniformly distributed by the array scattering sheet 4, the unit scale of the array scattering sheet is more than 50 microns, stripes generated by the light beam due to the second aspheric lens 5 are eliminated, the light beam is collimated into a thin light beam of quasi-parallel light by the first aspheric lens 3, finally stray light is eliminated by the round hole diaphragm 8, the laser stability is improved, the edge of the round hole is kept sharp, the diameter of the diaphragm is 1.5 +/-0.2 mm, and the stray light is eliminated, so that the lens is prevented from reflecting stray light.

As shown in fig. 1 and fig. 2, a light beam obtained by processing by the optical-mechanical structure of the light path shaping system 112 passes through the grating 2 in the optical signal collecting system 113 to obtain a light spot lattice 9 similar to that in fig. 3, and then is transmitted to the multi-pixel detection array 10 of the photodetector 1, so that the light spot is made to hit the center of each pixel as much as possible. The redundant stray light or external interference light is absorbed by the extinction structure 7, and a Brewster optical trap is adopted; the absorption rate of redundant light beams is larger than 0.99, the interference of reflected stray light to detector signals is prevented, and a high-pixel high-sensitivity detector is selected for the detector. The obtained signal is transmitted to the photoelectric signal processing device 11 to extract the signal.

The invention adopts a brand-new optical-mechanical structure and an optical signal collecting unit, and the sensor has simple structure and low cost. When the detector is used as a laser radar detector, the detection signal of an object with the reflectivity of 0.1 at a distance of 150m is 40% larger than that of a single photoelectric detector, the signal-to-noise ratio is higher than 2.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. The grating-based high-sensitivity optical signal detection optical machine structure is characterized by comprising a receiving system (111), an optical path shaping system (112) and an optical signal collecting system (113), wherein light beams sequentially pass through the optical signal collecting system (113) and the optical path shaping system (112) and then enter the receiving system (111), and the optical path shaping system (112) sequentially comprises a second aspheric lens (5), an array scattering sheet (4) and a first aspheric lens (3) from the incident direction of the optical signals.

2. The grating-based high-sensitivity optical signal detection opto-mechanical configuration of claim 1, wherein the optical signal collection system (113) employs a plano-convex lens (6) and is placed along the optical signal direction.

3. The grating-based high-sensitivity optical signal detection opto-mechanical configuration of claim 1, characterized in that the receiving system (111) comprises a photodetector (1), a grating (2) and a light extinction structure (7); the grating (2) is positioned in the receiving direction of the photoelectric detector (1), and the extinction structure (7) is arranged outside the grating (2) and the photoelectric detector (1).

4. The grating-based high-sensitivity optical signal detection optical-mechanical structure according to claim 1, wherein the optical path shaping system (112) further comprises a circular aperture stop (8), and the circular aperture stop (8) is disposed between the grating (2) and the first aspheric lens (3).

5. The grating-based high-sensitivity optical signal detection opto-mechanical arrangement according to claim 1, characterized in that the photodetector (1) is embodied as a multi-pixel detection array (10).

6. The grating-based high-sensitivity optical signal detection optical-mechanical structure according to claim 1, wherein the extinction structure (7) is configured to achieve an absorption rate of the laser light greater than 0.99.

7. The grating-based high-sensitivity optical signal detection opto-mechanical configuration of claim 1, characterized in that the grating (2) enables optical splitting to form a spot lattice (9) on the surface of the photodetector (1).