Photoelectric four-quadrant detector capable of filtering stray light and noise reduction method thereof

Abstract

The invention relates to the technical field of photoelectric four-quadrant detectors, in particular to a photoelectric four-quadrant detector capable of filtering stray light, which comprises four first photoelectric units in quadrant distribution, a non-photosensitive unit is fixedly mounted outside the four first photoelectric units, and a second photoelectric unit is fixedly mounted on the outer side of the non-photosensitive unit. The second photoelectric unit is designed outside a light path, the first photoelectric unit can receive an effective target signal, the second photoelectric unit cannot receive a light signal related to a target, diffuse reflection occurs when light irradiates the interior of the structure, impurity light in the space can be considered to be uniformly distributed, and the light intensity is improved. Since the newly added second photoelectric unit and the original first photoelectric unit do not receive the target effective signal, the position is close and the environment is the same, the signal generated by the newly added second photoelectric unit at the moment is the noise relative to the target object in the signal generated by the original first photoelectric unit. And the two parts are subtracted to obtain a target signal after noise filtering.

Description

Technical Field

[0001] The present invention relates to the technical field of optoelectronic quadrant detectors, and particularly to an optoelectronic quadrant detector capable of filtering stray light and a noise reduction method therefor. Background Art

[0002] A quadrant optoelectronic detector is an optoelectronic detection device formed by arranging four photodiodes with exactly the same performance according to the requirements of a rectangular coordinate. It is commonly used in laser guidance or laser collimation. It is made based on the photovoltaic effect in the principle of internal photoelectric effect. When the incident light spot falls on different positions of the photosensitive surface of the quadrant optoelectronic detector, different magnitudes of electrical signals will be output in each quadrant. By processing the signals output from the four quadrants, the centroid position of the incident light spot on the photosensitive surface can be determined, thereby judging the target position.

[0003] The wavelength range of sunlight is 200nm - 3000nm, while a fixed wavelength range, such as 1064nm, is often used during the use of the quadrant detector. Therefore, sunlight contains components that can be received by the detector. When used in a strong background light, the background light will be regarded as an effective signal, bringing noise interference of the background light; due to the influence of structural design, processing, etc., in actual use, optical signals on non-target optical paths will enter the equipment optical cabin, and after being reflected by the structure, they will finally irradiate on the detector and be regarded as effective signals, bringing noise interference of stray light; affected by the surrounding electromagnetic environment, some electrical noise signals will also be generated on the circuit. That is, the existing quadrant detectors are greatly affected by sunlight, stray light reflected by the internal structure, and interference from the surrounding environment during use. Summary of the Invention

[0004] The purpose of the present invention is to solve the following disadvantages in the prior art: the existing quadrant detectors are greatly affected by background light mainly composed of sunlight and stray light reflected by the internal structure during use, and an optoelectronic quadrant detector capable of filtering stray light interference is proposed.

[0005] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0006] An optoelectronic quadrant detector capable of filtering stray light includes four first optoelectronic units distributed in quadrants. A non-photosensitive unit is fixedly installed outside the four first optoelectronic units, a second optoelectronic unit is fixedly installed outside the non-photosensitive unit, and a structural housing is fixedly installed outside the second optoelectronic unit.

[0007] A noise reduction method for an optoelectronic quadrant detector capable of filtering stray light, the noise reduction method includes the following steps:

[0008] S1: During optical design, the second photoelectric unit is designed outside the optical path, enabling the original four-quadrant first photoelectric units to receive effective target signals, while the newly added second photoelectric unit cannot receive light signals related to the target.

[0009] S2: When light irradiates inside the structure, diffuse reflection occurs, and it can be considered that the impurity light in the space is evenly distributed.

[0010] S3: Since the newly added second photoelectric unit and the original first photoelectric units are close in position and in the same environment except for not receiving the effective target signal, the signal generated by the newly added second photoelectric unit at this time is the noise relative to the target object in the signal generated by the original first photoelectric units. Subtracting the two parts can obtain the target signal after filtering out the noise.

[0011] Compared with the prior art, the beneficial effects of the present invention are:

[0012] 1. During optical design, the newly added second photoelectric unit is designed outside the optical path, enabling the original four-quadrant first photoelectric units to receive effective target signals, while the newly added second photoelectric unit cannot receive light signals related to the target. When light irradiates inside the structure, diffuse reflection occurs, and it can be considered that the impurity light in the space is evenly distributed. Since the newly added second photoelectric unit and the original first photoelectric units are close in position and in the same environment except for not receiving the effective target signal, the signal generated by the newly added second photoelectric unit at this time is the noise relative to the target object in the signal generated by the original first photoelectric units. Subtracting the two parts can obtain the target signal after filtering out the noise, achieving the effect of filtering out stray light.

[0013] 2. Since the electrical interface materials of the first photoelectric unit and the second photoelectric unit are the same and their positions are close, if the signal traces of the two are made the same in PCB design, when the device is interfered by the external electromagnetic environment to generate noise signals, the common-mode noise in this part can be effectively removed by subtracting the two signals. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 FIG. is a partial three-dimensional structure schematic diagram of the first optical unit and the second optical unit in a photoelectric four-quadrant detector capable of filtering out stray light proposed by the present invention;

[0015] Figure 2 FIG. is a partial structure schematic diagram of a traditional four-quadrant detector;

[0016] Figure 3 FIG. is a partial structure schematic diagram of a photoelectric four-quadrant detector capable of filtering out stray light proposed by the present invention;

[0017] Figure 4 FIG. is a partial structure schematic diagram of a photoelectric four-quadrant detector capable of filtering out stray light when designing an asymmetric optical structure according to the present invention.

[0018] In the figure: 1 is the first optoelectronic unit, 2 is the non-photosensitive unit, 3 is the second optoelectronic unit, and 4 is the structural housing. Specific embodiments

[0019] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0020] Embodiment 1

[0021] Referring to Figure 1 and Figure 3 , an optoelectronic four-quadrant detector capable of filtering stray light includes four first optoelectronic units 1 distributed in a quadrant. The four first optoelectronic units 1 are distributed in a quadrant. A non-photosensitive unit 2 is fixedly installed outside the four first optoelectronic units 1. A second optoelectronic unit 3 is fixedly installed outside the non-photosensitive unit 2. A structural housing 4 is fixedly installed outside the second optoelectronic unit 3.

[0022] Referring to Figure 2 , the output electrical signals of the traditional four-quadrant detector are I1, I2, I3, and I4 respectively. Referring to Figure 3 , the output electrical signal of the new unit is I5. And when the optical structure is designed as a completely axisymmetric structure, that is, in the form of Figure 3 , the original used signals are I1, I2, I3, and I4, and the optimized used signals are I1 - I5, I2 - I5, I3 - I5, and I4 - I5.

[0023] During optical design, the newly added second optoelectronic unit 3 is designed outside the optical path, so that the original four first optoelectronic units 1 of the four quadrants can receive effective target signals, and the newly added second optoelectronic unit 3 cannot receive target-related optical signals. When light irradiates into the structure, diffuse reflection occurs, and it can be considered that the stray light in the space is evenly distributed. Since the newly added second optoelectronic unit 3 and the original first optoelectronic units 1 are close in position and in the same environment except for not receiving the effective target signals, the signal generated by the newly added second optoelectronic unit 3 at this time is the noise relative to the target object in the signal generated by the original first optoelectronic units 1. Subtracting the two parts can obtain the target signal after filtering the noise.

[0024] Meanwhile, when a second photoelectric unit 3 is newly added outside the non-photosensitive unit 2, the signal transmission path can be optimized. During the operation of the first photoelectric unit 1 in the four quadrants, the signal transmission is easily affected by electromagnetic interference. Since the electrical interface materials of the first photoelectric unit 1 and the second photoelectric unit 3 are the same and their positions are close, if the two signal traces are made the same in the PCB design, when the device is disturbed by the external electromagnetic environment to generate noise signals, the common-mode noise of this part can be effectively removed by taking the difference between the two signals, reducing the influence of electromagnetic interference on signal transmission (analogous to the principle of differential twisted pair).

[0025] Embodiment 2

[0026] When the optical structure is designed as an asymmetric structure, the second photoelectric unit 3 and the structural housing 4 can be designed with reference to Figure 4 Four newly added arc-shaped photoelectric units are combined into the second photoelectric unit 3. The original signals used are I1, I2, I3, and I4, and the signals used after optimization are I1 - I5.1, I2 - I5.2, I3 - I5.3, and I4 - I5.4.

[0027] A noise reduction method for a photoelectric four-quadrant detector capable of filtering stray light, the noise reduction method comprising the following steps:

[0028] S1: During optical design, the second photoelectric unit 3 is designed outside the optical path, so that the first photoelectric units 1 in the original four quadrants can receive effective target signals, and the newly added second photoelectric unit 3 cannot receive light signals related to the target;

[0029] S2: When light irradiates inside the structure, diffuse reflection occurs, and it can be considered that the stray light in the space is evenly distributed;

[0030] S3: Since the newly added second photoelectric unit 3 and the original first photoelectric unit 1 are close in position and in the same environment except for not receiving the effective target signal, the signal generated by the newly added second photoelectric unit 3 at this time is the noise relative to the target object in the signal generated by the original first photoelectric unit 1. Taking the difference between the two parts can obtain the target signal after filtering out the noise.

[0031] In the present invention, during optical design, the newly added second photoelectric unit 3 is designed outside the optical path, so that the original four first photoelectric units 1 in the four quadrants can receive effective target signals, and the newly added second photoelectric unit 3 cannot receive light signals related to the target. When light irradiates inside the structure, diffuse reflection occurs, and it can be considered that the stray light in the space is evenly distributed. Since the newly added second photoelectric unit 3 and the original first photoelectric unit 1 are close in position and in the same environment except for not receiving the effective target signal, the signal generated by the newly added second photoelectric unit 3 at this time is the noise relative to the target object in the signal generated by the original first photoelectric unit 1. Taking the difference between the two parts can obtain the target signal after filtering out the noise.

[0032] Meanwhile, when a second optoelectronic unit 3 is newly added outside the non-photosensitive unit 2, the signal transmission path can be optimized. During the operation of the first optoelectronic unit 1 in the four quadrants, the signal transmission is easily affected by electromagnetic interference. Since the electrical interface materials of the first optoelectronic unit 1 and the second optoelectronic unit 3 are the same and their positions are close, if the two signal traces are made the same in the PCB design, when the device is affected by the external electromagnetic environment interference and generates noise signals, the common-mode noise in this part can be effectively removed by taking the difference between the two signals, reducing the influence of electromagnetic interference on signal transmission (analogous to the principle of differential twisted pair).

[0033] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, making equivalent substitutions or changes should be covered within the protection scope of the present invention.

Claims

1. A photoelectric four-quadrant detector capable of filtering stray light, comprising four first photoelectric units (1) distributed in a quadrant manner, characterized in that, A non-photosensitive unit (2) is fixedly installed outside the four first optoelectronic units (1), a second optoelectronic unit (3) is fixedly installed outside the non-photosensitive unit (2), and a structural housing (4) is fixedly installed outside the second optoelectronic unit (3).

2. A noise reduction method for an optoelectronic four-quadrant detector capable of filtering stray light, characterized in that, The noise reduction method includes the following steps: S1: During optical design, the second optoelectronic unit (3) is designed outside the optical path, so that the original four first optoelectronic units (1) in the four quadrants can receive effective target signals, while the newly added second optoelectronic unit (3) cannot receive optical signals related to the target. S2: When light irradiates the inside of the structure, diffuse reflection occurs, and it can be considered that the impurity light in the space is evenly distributed. S3: Since the newly added second optoelectronic unit (3) and the original first optoelectronic unit (1) are close in position and in the same environment except that the newly added second optoelectronic unit (3) does not receive the effective target signal, the signal generated by the newly added second optoelectronic unit (3) at this time is the noise relative to the target object in the signal generated by the original first optoelectronic unit (1). By taking the difference between the two parts, the target signal after noise filtering can be obtained.

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