KR100337011B1 - Lidar scanning apparatus for inspecting dust-exhaust - Google Patents

Abstract

The present invention relates to a remote standby analysis scanning lidar device using a laser; The objective is to provide a portable lidar scanning device for monitoring dust emission, which can maintain the polarization of the laser, eliminate the scattered light and use a single optical system as a transmitter-receiver and measure the atmospheric dust in three dimensions. have.

The present invention for achieving the above object is irradiated in three dimensions with the laser generating unit (2) for generating a laser light, the scanning mirrors (19, 18) for reflecting the laser light of the laser generating unit (2) Scanning mirror rotating shafts 21 and 22, a laser transmitting optical system A for irradiating the light reflected by the reflecting mirror into the atmosphere, and a laser beam irradiated by the laser transmitting optical system A are atmosphere. It consists of a laser receiving optical system (B) that receives laser light that is backscattered back in dust, etc., so that the polarization of the laser is maintained with the configuration and arrangement of the optical system so that one optical system can be used for both transmission and reception. It is a scanning type lidar device for dust emission monitoring, which is easy to carry by reducing the size of a large-diameter mirror by blocking the laser beam by using a rotating mirror.

Description

LIDAR SCANNING APPARATUS FOR INSPECTING DUST-EXHAUST}

The present invention relates to a remote standby analysis scanning lidar device using a laser; More specifically, the present invention relates to a portable dust emission monitoring scanning lidar device that can use a single optical system for both transmission and reception, maintains polarization of a laser, and can measure atmospheric dust in three dimensions.

The distribution of air molecules or dust in the atmosphere provides important information for estimating the degree of mixing of contaminants in the atmosphere or for studying phenomena such as long-distance transport of contaminants. A transmission optical system that emits a light source such as a light into the atmosphere, and a reception optical system that receives the light reflected by the air molecules and dust in the atmosphere (back scattering, BACK-SCATTERING) through a large-caliber telescope. There are many problems with sorting because it is configured

In addition, in order to scan the laser three-dimensionally (SCANNING) should be able to rotate the direction of the laser in two axes (X-AXIS, Y-AXIS). In this case, when irradiating the laser in the horizontal direction, the laser must be sufficiently enlarged due to the problem of eye protection (EYE SAFETY), and for this purpose, two telescopes of large diameter are required. When two telescopes are matched together, the transmitting optical system and the receiving optical system are placed on one axis. Therefore, the receiving sensor is controlled by a transmitting laser in a photodegrader, a lens, a large diameter mirror, and a 1/4 phase adjuster (1/4 λ PLATE). This is a problem because it is affected by the generated scattered light. In general, expensive special optical systems and DEPOLARIZER are used to prevent such phenomenon. In general, when a special expensive optical system is used, scattering signals are insignificant, and thus optical amplifiers (PHOTO MULTIPLIER TUBE, PMT) are used. By controlling the voltage applied to the signal induced noise (SIGNAL INDUCED NOISE) can be eliminated, but the general optical components cause a large amount of scattered signal by the laser light of several MW / ㎠. In the latter case, the signal induced noise cannot be eliminated by the electric method, which is a problem. In FIG. 1, scattering and reflection signals generated by the optical systems of 4, 5, 6, 7, 16, and 17 correspond to this.

The present invention has been made to solve such a conventional problem, in the conventional laser scanning type lidar device (LIDAR, LASER RADAR) LIDAR, LASER RADAR preserves the polarization of the received signal, removes scattered light and transmits one optical system Portable dust emission monitoring that can measure air pollution in three dimensions to measure the degree of pollution and movement in the air, and to prevent environmental pollution by eliminating various problems caused by the integration of reception and reception An object of the present invention is to provide a scanning lidar device.

1 is a detailed development view of the scanning lidar device for dust emission monitoring of the present invention

2 is an overall configuration diagram of the present invention lidar injection device

<Description of the symbols for the main parts of the drawings>

(1) telescopic support (2) laser light generator

(3) primary beam expander

(4) Holes to control the amount of scattered and reflected light in the telescope's primary and secondary mirrors

(5) Collimation lens (6) 1/4 λ phase adjuster

(7) Polarization Photodegraders (8) Center Block Spatial Filters

(9) INTERFERENCE FILTER (10) Lens

(11) Pinholes for passing scattered images

(12) Spatial filter to block scattered light (13) Lens

(14) Pinholes to control the telescope's vision

(15) PHOTO MULTIPLIER TUBE, PMT

(16) (17) Primary, secondary mirrors of telescopes (18), (19) Primary, secondary scanning mirrors

(20) Laser power supply (21), (22) Scanning mirror rotating shaft

(A) Transmission optical system (B) Reception optical system

(C) Laser generation unit (D) Laser three-dimensional irradiation unit

Referring to the configuration and operation of the embodiment of the present invention in detail with reference to the accompanying drawings as follows.

1 is a detailed development view of the dust emission monitoring scanning device of the present invention, since the laser light pumped by the diode laser is generally less than 1 mm in size and fills all surfaces of the mirrors 16 and 17 of the large-diameter telescope. In order to increase the size of the laser, the primary beam expander (3) is used as the device for enlarging the light to increase the size of the laser. After expanding the laser light as described above, before passing through the polarization photodegrader 7, a space filter 8 (CENTER BLOCKING FILTER) blocking the center portion of the laser cross section is passed. The size of the spatial filter 8 is determined in consideration of the fact that the laser central part is blocked at the secondary mirror 17 of the telescope. The use of the spatial filter 8 is to prevent the laser from being reflected by the lens 5 or the secondary mirror 17 and incident on the optical amplifier tube 15. The vertically polarized laser passes through the polarized light decomposer 7 and again passes through the 1/4 lambda phase controller 6 to become circularly polarized light and then passes through the lens 5 to be irradiated into the atmosphere. The signal back-scattered by the air molecules or dust particles passes through the 1/4 λ phase regulator 6 again. When scattered and the polarized light is preserved, the signal is horizontally polarized while passing through the phase regulator 6. Reflection is made in the polarized light splitter 7 and passes through the interference filter 9 and the lens 10 to pass through the small hole 11 for adjusting the view of the large-diameter telescope. At this time, the lens 10 is placed as close as possible to the polarized light decomposer 7 so that the scattered image IMAGE passes through the small hole 11. A small amount of scattered light is again blocked by the spatial filter 12, but the backscattered signal corresponding to the signal is almost blocked and passes. By adjusting the position and the focal length of the lens 13 so that the image of the small hole 11 is actually formed in the hole 14 for controlling the field of view of the telescope in front of the optical amplification tube 15. The small hole in the window allows for arbitrary adjustment of the field of view. The device can arbitrarily adjust the telescope's vision even with one small hole, and it can know the preservation state of polarization, so it is possible to know the characteristics of atmospheric particles (air molecules, dust) causing scattering, and commercially available optical parts (lenses). , A mirror, a photodecomposer, etc.) can remove scattered light by the optical system, so that an expensive optical system is not necessary.

FIG. 2 is an overall configuration diagram of the scanning lidar device according to the present invention, in which a configuration of the lidar scanning device required for SENDING a laser beam in the air is shown as an actual attached model including two rotating shafts and their supports. . The laser power supply 20, the laser light generator 2, and the primary beam expander 3 are fixed separately from the scanning unit and, unlike the conventional apparatus, in which the laser is moved and scanned by two-axis motors, rotation is performed. The laser beam is scanned in three dimensions using two scanning mirrors 19 and 18. The two axes of the mirror used for scanning are composed of a primary scanning axis 22 and a secondary scanning axis 21. Therefore, the laser is irradiated three-dimensionally in the atmosphere through the primary-secondary scanning mirrors 19 and 18 having the rotating scanning axis. Therefore, since the cross section of the laser beam is not greatly enlarged, the small mirror of the primary scanning mirror 19 and the secondary scanning mirror 18 is sufficient. This method has the advantage that the laser can be scanned in the three-dimensional direction while fixing the position of the laser generating device (2) and can be manufactured at a lower cost than conventional large-diameter scanning system because it can also be scanned by a small diameter mirror. There is an advantage.

In a scanning lidar for dust emission monitoring using a LiDAR that uses one optical system as both a transmitter and a receiver, the laser power supply 20 and the laser generator 2 and the generated laser light are enlarged. A laser generating unit (C) consisting of a primary beam expander (3), a three-dimensional irradiation unit (D) consisting of two scanning mirrors (19, 18) rotating under the laser light of the laser generating unit (C); A small hole 4 for adjusting the amount of the background signal by the polarized light splitter 7, the 1/4 λ phase adjuster 6, the collimator lens 5, and the laser beam of the laser 3D irradiation unit D; A laser transmission optical system A formed by arranging primary and secondary mirrors 16 and 17, a small hole 11 through which scattered images pass, a spatial filter 12 and a lens 13 that block scattered light, The eyelet 14 and the optical amplification tube 15 are properly arranged to control the field of view of the telescope. The laser beam irradiated by the transmitting optical system A is composed of a laser receiving optical system B for receiving a laser beam that is scattered back in dust or the like in the air, and the two small beams are axially rotated at right angles to each other. The portable laser scanning mirror (18, 19) can be used to irradiate the laser in three dimensions to measure various optical coefficients of air molecules and dust in the air in three dimensions. Device.

Further, in the laser receiving optical system (B) and the transmitting optical system (A), the light irradiated into the atmosphere by the combination of the 1/4 λ phase regulator 6 and the polarization photolyzer 7 is scattered back by air molecules or dust. Only the light in which the polarization is preserved is reflected through the polarization photo splitter 7 to be incident on the optical amplifier 15 so that the polarization is preserved.

And the position and focus of the lens 13 so that the image of the small hole 11 in the laser receiving optical system B forms a real image in the small hole 14 that controls the view of the telescope in front of the optical amplifier tube 15. By adjusting the distance, even a small hole of constant size can continuously change the field of view (tens of μs to hundreds of μs).

In addition, in the laser transmission optical system A, a polarization photodegrader 7, a lens 5, a primary-secondary mirror 16, 17, a 1/4 λ phase regulator 6, etc. are generated by a transmission laser. In order to prevent the influence of various scattered light, low cost such as 1/4 λ phase adjuster 6, polarized light decomposer 7, interference filter 9, lens 10, eyelet 11 and spatial filter 12 There is a characteristic that the scattered light by the optical system is removed by arranging commercially available parts appropriately.

The effects of the present invention that can be expected by the configuration and action as described above are as follows.

A single optical system can be used for both transmission and reception, and the proper configuration and arrangement of the optical system maintains the polarization of the laser, blocks the scattered light from the optical system, and uses the same telescope to transmit the scattered light in the atmosphere. It is a very useful invention to solve the eye protection problem by using for transmission and to irradiate the laser light in three dimensions by using the rotating mirror to reduce the size of the large-diameter mirror and to be easy to carry and to use for dust emission monitoring.

Claims (4)

In a scanning lidar device for dust emission monitoring using a lidar (LIDAR) that uses one optical system for both transmission and reception, A laser generator (C) comprising a primary beam expander (3) for enlarging the laser light generated by the laser power supply device (20) and the laser generator (2); A three-dimensional irradiation unit (D) for three-dimensional irradiation in the air through two scanning axes (22) (21) and scanning mirrors (19, 18) configured to rotate the laser light; Polarization photo splitter (7), 1/4 λ phase adjuster (6), collimator lens (5), small holes (4) to control the amount of light, eye protection and scattering signal acquisition A laser transmission optical system (A) is arranged in which primary and secondary mirrors (16, 17) are sequentially arranged, and a polarization photo splitter (7) for reflecting backscattered signals in the atmosphere, and an interference filter for removing background signals. A spatial filter 12 for blocking the scattered light through the small hole 11 through the lens 10 and the lens 10, the lens 13, the small hole 14 for controlling the field of view of the telescope, and the light. It consists of a laser receiving optical system (B) in which an amplifying tube (15) is arranged, and irradiates a laser in a three-dimensional direction by using two small-sized scanning mirrors (18, 19) rotating in the perpendicular direction to each other. It is possible to measure various optical coefficients of air molecules or dust in three dimensions, and it is easy to carry. Emission monitoring referred to a device for scanning. The method of claim 1, In the laser receiving optical system (B) and the transmitting optical system (A), the light irradiated into the atmosphere by the combination of the 1/4 λ phase regulator 6 and the polarization photolyzer 7 is scattered back by air molecules or dust. Scanning lidar apparatus for dust emission monitoring, characterized in that only the light in which polarization is preserved is reflected through the polarization photo splitter (7) to be incident on the optical amplifier tube (15). The method of claim 1, In the laser receiving optical system B, the position and focal length of the lens 13 are adjusted so that the image of the small hole 11 is actually formed in the small hole 14 that controls the view of the telescope in front of the optical amplifier tube 15. Scanning type for dust emission monitoring, characterized by continuously changing the field of view (several μs-hundreds of microns) and blocking the scattered light from the optical system, even with small holes of constant size. Is the device. The method of claim 1, In the laser transmission optical system A, various types of light generated in the polarization photodegrader 7, the lens 5, the primary-secondary mirrors 16 and 17, and the 1/4 λ phase regulator 6 are generated by the transmission laser. In order to prevent the influence of scattered light, low-cost commercial use such as a 1/4 λ phase adjuster 6, a polarized light decomposer 7, an interference filter 9, a lens 10, a small hole 11, and a spatial filter 12 An apparatus for arranging dust and removing scattered light by an optical system.