Single-receiving double-view-field laser range finder

Abstract

The invention provides a single-receiving double-field-of-view laser range finder which can realize simultaneous implementation of multiple functional tasks and is suitable for multiple scenes. Comprising a laser device beam expanding lens assembly and a light beam receiving assembly which are installed together in parallel, and the laser device beam expanding lens assembly comprises a laser device used for emitting laser beams, a beam expanding lens negative lens set used for diverging the laser beams and a beam expanding lens positive lens set used for converging the laser beams which are sequentially arranged in the direction of an emitting light path. The light beam receiving assembly comprises a first lens, a second lens, a third lens and a color separation lens which are sequentially arranged in the direction of a receiving light path, the color separation lens is obliquely arranged to divide a laser beam into two paths, one path of the two paths is transmitted to a first light filter for distance measurement, and the other path of the two paths is transmitted to a second light filter for communication after passing through a fourth lens; the first lens and the fourth lens are plano-convex lenses, and the second lens and the third lens are meniscus lenses.

Description

Technical Field

[0001] The present invention relates to the technical field of laser ranging, and specifically to a single-receiver dual-field-of-view laser rangefinder. Background Art

[0002] Laser is a major invention in the 1960s of the 20th century. Due to its characteristics such as good directivity, high brightness, monochromaticity, and good coherence, it has been widely used. For example, it has been widely used in technical fields such as laser processing, laser cutting, laser ranging, laser guidance, laser communication, laser rapid prototyping, laser welding, laser engraving, laser energy, laser surgery, and laser weapons. Laser ranging is invented by making use of the characteristics of laser such as good monochromaticity and directivity. Since the speed of light propagation in a uniform medium is constant, a highly focused laser beam is emitted by a laser to a target object. Part of the laser energy is absorbed by the target object, and part of the laser is reflected back. The reflected laser beam is received by a receiver, and the time when the laser beam is received is recorded and converted into an electrical signal. Then, by measuring the time required for the laser beam to travel from emission to reception, the time for the laser beam to propagate in the air is obtained. Based on the propagation speed of light in the medium and the measured time, the distance between the target object and the rangefinder is calculated. Laser communication uses a laser beam as an information carrier and transmits data by modulating characteristics such as the intensity, frequency, or phase of the laser. The carrier is restored into information such as sound and image by a detector and a demodulator at the receiving end.

[0003] Given different measurement scenarios and methods, the commonly used methods for laser ranging currently are: pulse method, phase method, triangulation method, etc. Each method has its own characteristics and applicable scenarios. Among them, the pulse method: uses a laser with a high peak power and a highly sensitive receiver, and calculates the distance by measuring the reflection time and the round-trip time difference of the laser on the target object. This method has the characteristics of high-precision and high-speed ranging; the phase method: uses a laser light source with good coherence and a complex interference system, and calculates the distance by measuring the phase change of the laser reflected on the target object. This method has the characteristics of high-precision and low noise; the triangulation method: uses precise measurement equipment and algorithms, and calculates the distance by measuring the reflection angle of the laser on the target object and the known distance between the laser and the receiver. This method has the characteristics of non-contact and high-precision; for the method of realizing laser ranging by the pulse method, after decades of development, it has been maturely applied in many industries, with various sizes and wide classifications, such as military equipment, marine equipment, aerospace equipment. In recent years, many products have also been developed for use in civilian equipment. Common pulsed lasers include solid lasers such as gallium arsenide semiconductor lasers, rubies, neodymium glass, erbium glass, etc. However, with the continuous in-depth understanding of the laser ranging field, single-function laser ranging can no longer meet the needs of many scenarios. Therefore, people have continuously tried different applications in different scenarios, such as folding the receiving optical path through different prisms to form two or more optical paths with different wavelength bands, and realizing multiple functions by different receiving methods according to needs. However, no matter which application scenario, if it is necessary to meet multiple functions, such as realizing laser ranging or laser communication, etc., it is necessary to configure corresponding modules to adapt to the laser, and multiple function tasks cannot be carried out simultaneously, and the use is relatively limited. Summary of the Invention

[0004] In view of the above problems, the present invention provides a single-receiver dual-field-of-view laser rangefinder, which can perform multiple function tasks simultaneously and is applicable to multiple scenarios.

[0005] The present invention adopts the following technical solutions. A single-receiver dual-field-of-view laser rangefinder includes a laser beam expander lens assembly and a received beam assembly installed in parallel. The laser beam expander lens assembly includes a laser for emitting a laser beam, a negative lens group of the beam expander for diverging the laser beam, and a positive lens group of the beam expander for converging the laser beam, which are sequentially arranged along the emission optical path direction. The received beam assembly includes a first lens, a second lens, a third lens, and a dichroic lens, which are sequentially arranged along the received optical path direction. The dichroic lens is inclined to divide the laser beam into two paths. One path of the two paths is transmitted to the first filter for ranging, and the other path is transmitted to the second filter for communication after passing through the fourth lens. The first lens and the fourth lens are both plano-convex lenses, and the second lens and the third lens are both meniscus lenses.

[0006] Further, the negative lens group of the beam expander includes an eyepiece and a fifth lens, and the positive lens group of the beam expander includes a sixth lens and a seventh lens. The fifth lens is a double concave negative lens, and the sixth lens and the seventh lens are both meniscus positive lenses;

[0007] Further, the laser beam expander assembly further includes a protective cover, a beam expander seat, and a beam expander barrel. The protective cover and the beam expander barrel are respectively installed at both ends of the beam expander seat. A negative lens seat is installed inside the beam expander seat. The light emitting end of the laser is connected to the protective cover. The eyepiece and the fifth lens are installed inside the negative lens seat, and the sixth lens and the seventh lens are installed at the light emitting end of the beam expander barrel;

[0008] Further, a photodetector is inserted and installed on the protective cover between the laser and the negative lens seat;

[0009] Further, the outer wall of the negative lens seat has a threaded portion and a non-threaded portion. The negative lens seat is connected to the beam expander barrel through the threaded portion, and there is an interference fit between the non-threaded portion of the negative lens seat and the beam expander barrel;

[0010] Further, a plurality of screw holes are symmetrically arranged along the circumferential direction on the outer wall of the beam expander barrel. After the screws pass through the screw holes, they are in contact with the non-threaded portion of the negative lens seat;

[0011] Further, the received light beam assembly further includes a receiving cylinder body. The beam expander seat is installed on the receiving cylinder body. The dichroic lens is installed inside the receiving cylinder body through a fixing seat and fixed by a first retaining ring. The first lens, the second lens, and the third lens are all fixed inside the receiving cylinder body through second retaining rings respectively;

[0012] Further, the receiving cylinder body is provided with a first interface and a second interface. A cover shell is installed on the receiving cylinder body at the position of the second interface. The first filter is installed inside the receiving cylinder body at the position of the first interface, and the fourth lens and the second filter are installed inside the cover shell;

[0013] Further, the laser rangefinder further includes a main control board, a drive board, a ranging amplifier board, and a communication amplifier board. The ranging amplifier board is installed on the receiving cylinder body at the position of the first interface, the communication amplifier board is installed on the receiving cylinder body at the position of the second interface, the main control board is installed at the top of the receiving cylinder body, and the drive board is installed on the receiving cylinder body on the side of the laser;

[0014] Further, the drive board is connected to both the laser and the main control board and is used to drive the laser to generate transmitted laser;

[0015] The ranging amplifier board is connected to the main control board and is used to receive the laser beam emitted by the first filter and feedback and output it to the main control board to achieve ranging;

[0016] The communication amplifier board is connected to the main control board and is used to receive the laser beam emitted by the second filter and feedback and output it to the main control board to achieve communication.

[0017] The beneficial effect of the present invention is that the laser beam expander lens assembly and the received beam assembly are installed in parallel, and the dichroic lens is used in the received beam assembly to divide the laser beam into two paths, so that the ranging and communication functions can be realized, which are independent of each other and not affected by other functional tasks, thus being applicable to various scenarios and modes and having good economic use value. Description of the Drawings

[0018] Figure 1 is the structural schematic diagram of the present invention;

[0019] Figure 2 is the schematic diagram of the emission optical path in the present invention;

[0020] Figure 3 is the schematic diagram of the received optical path in the present invention;

[0021] Figure 4 is the structural schematic diagram of the laser beam expander lens assembly in the present invention;

[0022] Figure 5 is the cross-sectional view of the laser beam expander lens assembly in the present invention;

[0023] Figure 6 is the cross-sectional view of the received beam assembly in the present invention;

[0024] Figure 7 is the circuit block diagram of the present invention. Detailed Embodiments

[0025] Such as Figures 1 to 7As shown in the figure, a single-receiver dual-field-of-view laser rangefinder in the present invention includes a laser beam expander assembly 501 and a received beam assembly 502 that are installed in parallel. The laser beam expander assembly includes a laser 301 for emitting a laser beam, a beam expander negative lens group for diverging the laser beam, and a beam expander positive lens group for converging the laser beam, which are arranged in sequence along the emission optical path. The received beam assembly includes a first lens 201, a second lens 202, a third lens 203, and a dichroic lens 204, which are arranged in sequence along the received optical path. The dichroic lens 204 is inclined to divide the laser beam into two paths. One path is transmitted to a first filter 207 for ranging, and the other path is transmitted to a second filter 206 after passing through a fourth lens 205 for communication. The first lens 201 and the fourth lens 205 are both plano-convex lenses, and the second lens 202 and the third lens 203 are both meniscus lenses.

[0026] The beam expander negative lens group includes an eyepiece 101 and a fifth lens 102, and the beam expander positive lens group includes a sixth lens 103 and a seventh lens 104. The fifth lens 102 is a double-concave negative lens, and the sixth lens 103 and the seventh lens 104 are both meniscus positive lenses.

[0027] Specifically, the first lens 201 is used to compress the marginal rays of the returned laser beam to allow more returned laser beams to enter the lens of the receiving assembly.

[0028] The second lens 202 and the third lens 203 are used to optimize spherical aberration and sine aberration to improve the overall quality of the returned laser beam.

[0029] The dichroic lens 204 is a dichroic short-wave pass filter and dichroic lens 204, which is used to divide the reflected laser beam into two laser beams of different bands. One laser beam is transmitted to the first filter 207 (an avalanche photodiode APD can be set at the first interface. The avalanche photodiode APD is an electronic device on the ranging amplifier board 504, and the avalanche photodiode APD receives the outgoing light of the first filter 207). The avalanche photodiode APD converts the received laser signal into a corresponding electrical signal, and after corresponding processing on the ranging amplifier board 504, it is sent to the main control board to achieve ranging. The other laser beam is transmitted to the second filter 206 after passing through the fourth lens 205. The outgoing light of the second filter 206 is transmitted to a corresponding sensor according to requirements (the sensor is an electronic device on the communication amplifier board 505). The sensor also converts the received laser signal into a corresponding electrical signal, and after corresponding processing on the communication amplifier board 505, it is sent to the main control board to achieve communication. For example, it is transmitted to a photodiode to achieve laser communication, transmitted to an image sensor to achieve image transmission, transmitted to a measuring instrument to achieve measurement, transmitted to a gun sight to achieve target locking, and can also be transmitted to devices such as a telescope, a telescopic sight, and a pod to achieve different functions.

[0030] The fourth lens 205 is used to compensate for imaging quality problems caused by the characteristics of the lens system itself (such as spherical aberration, chromatic aberration, etc.), so as to obtain a clearer image and the error of the overall system focal length conductor;

[0031] The first filter 207 and the second filter 206 are both used to filter out optical beams in other bands and other stray light except for the beams in a specific band. In addition to the filters, antireflection paint, antireflection threads, etc. can be added inside the receiving cylinder 402 to improve the quality of the received beam;

[0032] The eyepiece 101 and the fifth lens 102 form a beam expander negative lens group, which is used to diverge the beam emitted by the laser 301, increase the diameter of the laser beam, optimize the spherical aberration effect, and for the laser beam passing through the beam expander negative lens group, the spot size is enlarged while the total energy of the laser remains unchanged;

[0033] The sixth lens 103 and the seventh lens 104 form a beam expander positive lens group. When the beam passes through the fifth lens 102, the laser beam can be re-converged through the beam expander positive lens group, and parallel transmission of the beam over a long distance can be achieved.

[0034] The beam expander assembly of the laser 301 further includes a protective cover 302, a beam expander seat 307, and a beam expander barrel 305. The protective cover 302 and the beam expander barrel 305 are respectively installed at both ends of the beam expander seat 307. The protective cover 302 can be used to ensure the cleanliness between the laser 301 and the beam expander negative lens group, and prevent external media such as dust, water vapor, and water droplets from affecting the transmission of the laser beam. A negative lens seat 306 is installed inside the beam expander seat 307. The output optical end of the laser 301 is connected to the protective cover 302. The eyepiece 101 and the fifth lens 102 are installed inside the negative lens seat 306, and the sixth lens 103 and the seventh lens 104 are installed at the output end of the beam expander barrel 305;

[0035] An optoelectronic detector 303 is inserted on the protective cover 302 between the laser 301 and the negative lens seat 306. The optoelectronic detector 303 is mainly used to detect the laser signal and convert it into an electrical signal for subsequent processing and analysis. After the laser emitted by the laser 301 hits the target object and is reflected back, it is received by the optoelectronic detector 303. Components such as photodiodes or photomultiplier tubes inside the optoelectronic detector will convert the received optical signal into a current or voltage signal and process it into distance information.

[0036] The outer wall of the negative lens holder 306 has a threaded portion and a non-threaded portion. The negative lens holder 306 is connected to the beam expander barrel 305 through the threaded portion, and there is an interference fit between the non-threaded portion of the negative lens holder 306 and the beam expander barrel 305; the negative lens holder 306 controls the position of the eyepiece 101 in the laser beam emission direction through the threaded portion, and ensures the uniqueness of the circumferential position through the slight interference fit between the non-threaded portion of the outer cylindrical surface and the corresponding position of the beam expander barrel 305. After the position is adjusted, it can be fastened by adjusting the screw 304, or the glue can be dropped into the screw hole by means of dispensing to firmly fix the beam expander barrel 305 and ensure the stable position of the eyepiece 101 after adjustment.

[0037] Four screw holes are symmetrically arranged along the circumferential direction on the outer wall of the beam expander barrel 305. After the screw 304 passes through the screw hole, it abuts against the non-threaded portion of the negative lens holder 306. The centering position of the negative lens holder 306 can be adjusted by the screw 304, that is, the positions of the eyepiece 101 and the fifth lens 102 are adjusted to ensure the accuracy and stability of the laser beam propagation.

[0038] The receiving beam assembly further includes a receiving cylinder 402. The beam expander holder 307 is installed on the receiving cylinder 402. The dichroic lens 204 is installed in the receiving cylinder 402 through the fixing seat 403 and then fixed by the first retaining ring 404. The first lens 201, the second lens 202, and the third lens 203 are respectively fixed in the receiving cylinder 402 through the second retaining ring 407, the second retaining ring 406, and the second retaining ring 405; it should be noted that not all lenses use fixed retaining rings, and the lenses can also be fixed and positioned by other means, such as bonding with glue.

[0039] The receiving cylinder 402 is provided with a first interface 408 and a second interface 409. A cover 401 is installed on the receiving cylinder 402 at the position of the second interface 409. The first filter 207 is installed in the receiving cylinder 402 at the position of the first interface 408, and the fourth lens 205 and the second filter 206 are installed in the cover 401.

[0040] The laser rangefinder further includes a main control board 503, a drive board 506, a ranging amplifier board 504, and a communication amplifier board 505. The ranging amplifier board 504 is installed on the receiving cylinder 402 at the position of the first interface 408, the communication amplifier board 505 is installed on the receiving cylinder 402 at the position of the second interface 409, the main control board 503 is installed at the top of the receiving cylinder 402, and the drive board 506 is installed on the receiving cylinder 402 on the side of the laser 301;

[0041] Among them, the drive board 506 is connected to both the laser 301 and the main control board 503 and is used to drive the laser 301 to generate and emit laser light;

[0042] The ranging amplifier board 504 is connected to the main control board 503, and is used to receive the laser beam emitted from the first filter 207, and amplify and feedback it to the main control board 503 to achieve ranging;

[0043] The communication amplifier board 505 is connected to the main control board 503, and is used to receive the laser beam emitted from the second filter 206, and amplify and feedback it to the main control board 503 to achieve communication;

[0044] Both the ranging amplifier board 504 and the communication amplifier board 505 convert the optical signal into an electrical signal according to the received laser signal, and transfer it to the main control board 503 for corresponding processing to achieve different functions;

[0045] The main functions of the main control board 503 are to achieve system monitoring, data processing, control decision-making, communication coordination, communication with the upper computer, safety protection, fault diagnosis, scalability management, etc.; it can achieve communication with external devices, control of various signals, processing of main wave and echo digital signals, etc.

[0046] In the present invention, the laser 301 is responsible for emitting an accurate beam, the beam expander assembly of the laser 301 is responsible for condensing light and transmitting light with a stable optical path, and the received beam assembly is responsible for receiving the returned optical path. The present invention can achieve functions such as ranging, image transmission, and laser communication. By obliquely setting the dichroic lens 204, the laser beam is divided into two optical paths with different wavelength bands. One optical path is transmitted to the first filter 207 and undergoes corresponding processing to achieve ranging, and the other optical path is transmitted to the second filter 206 after passing through the fourth lens 205 and undergoes corresponding processing to achieve communication. Different functions can also be achieved by selecting or confirming corresponding optoelectronic devices according to the application scenario.

[0047] The present invention has the following advantages:

[0048] 1. Long ranging distance, high accuracy, and stable data;

[0049] 2. The received beam assembly uses a dichroic lens to divide the optical path into two paths, suitable for a variety of scenarios and modes;

[0050] 3. Multiple tasks can be carried out simultaneously and independently, without being affected by other tasks;

[0051] 4. The optical path adjustment is simple and convenient;

[0052] 5. It can filter out stray light and effectively protect the stability of the optical path transmission;

[0053] 6. Light weight and small volume.

[0054] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above-described exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, in any regard, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be embraced within the present invention. Any reference signs in the claims should not be construed as limiting the claims involved.

[0055] In addition, it should be understood that although this specification is described in terms of embodiments, not every embodiment only contains an independent technical solution. This narrative manner of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A single-receiver dual-field-of-view laser rangefinder, characterized in that: It includes a laser beam expander assembly and a receiving light beam assembly installed in parallel. The laser beam expander assembly includes a laser for emitting a laser beam, a beam expander negative lens group for diverging the laser beam, and a beam expander positive lens group for converging the laser beam, which are sequentially arranged along the emitting light path. The receiving light beam assembly includes a first lens, a second lens, a third lens, and a color separation lens, which are sequentially arranged along the receiving light path. The color separation lens is tilted to separate the laser beam into two paths, one of which is transmitted to a first filter for ranging, and the other is transmitted to a second filter after passing through a fourth lens for communication. The first lens and the fourth lens are both plano-convex lenses, and the second lens and the third lens are both meniscus lenses.

2. The single-receiving dual-field-of-view laser rangefinder according to claim 1, characterized in that: The negative lens group of the collimator includes an eyepiece and a fifth lens, and the positive lens group of the collimator includes a sixth lens and a seventh lens. The fifth lens is a double concave negative lens, and the sixth lens and the seventh lens are both meniscus positive lenses.

3. The single-receiving dual-field-of-view laser rangefinder according to claim 1, characterized in that: The laser beam expander assembly also includes a protective cover, a beam expander seat, and a beam expander barrel. The protective cover and the beam expander barrel are respectively installed at both ends of the beam expander seat. A negative lens seat is installed in the beam expander seat. The output light end of the laser is connected to the protective cover, the eyepiece and the fifth lens are installed in the negative lens seat, and the sixth lens and the seventh lens are installed at the output end of the beam expander barrel.

4. The single-receiving dual-field-of-view laser rangefinder according to claim 3, characterized in that: A photoelectric detector is inserted on the protective cover located between the laser and the negative lens seat.

5. The single-receiving dual-field-of-view laser rangefinder according to claim 3, characterized in that: The outer wall of the negative lens holder has a threaded portion and a non-threaded portion, the negative lens holder is connected to the beam expander barrel via the threaded portion, and the non-threaded portion of the negative lens holder is interference fit with the beam expander barrel.

6. The single-receiving dual-field-of-view laser rangefinder according to claim 3, characterized in that: A plurality of screw holes are symmetrically arranged along the circumferential direction on the outer wall of the beam expanding lens barrel, and the screws are in conflict with the non-threaded portion of the negative lens holder after passing through the screw holes.

7. The single-receiving dual-field-of-view laser rangefinder according to claim 3, characterized in that: The receiving light beam assembly also includes a receiving cylinder, the beam expander seat is installed on the receiving cylinder, the color separation lens is installed in the receiving cylinder through a fixing seat and then fixed by a first pressing ring, and the first lens, the second lens, and the third lens are respectively fixed in the receiving cylinder through a second pressing ring.

8. The single-receiving dual-field-of-view laser rangefinder according to claim 7, characterized in that: The receiving cylinder is provided with a first interface and a second interface, a cover is installed on the receiving cylinder at the second interface position, the first filter is installed in the receiving cylinder at the first interface position, and the fourth lens and the second filter are installed in the cover.

9. The single-receiving dual-field-of-view laser rangefinder according to claim 8, characterized in that: The laser rangefinder also includes a main control board, a drive board, a ranging amplifier board, and a communication amplifier board. The ranging amplifier board is installed on the receiving cylinder located at the first interface position, the communication amplifier board is installed on the receiving cylinder located at the second interface position, the main control board is installed on the top of the receiving cylinder, and the drive board is installed on the receiving cylinder located on the laser side.

10. The single-receiving dual-field-of-view laser rangefinder according to claim 9, characterized in that: The driving board is connected to the laser and the main control board, and is used to drive the laser to generate laser light; The distance measuring amplifier board is connected to the main control board, and is used to receive the laser beam emitted by the first filter, and feed back the laser beam to the main control board to achieve distance measurement; The communication amplifier board is connected to the main control board, and is used to receive the laser beam emitted by the second filter, and feed back the output to the main control board to achieve communication.

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