Laser measurement equipment based on variable beam light path and electronic equipment thereof

Abstract

The invention provides laser measurement equipment based on a variable beam light path and electronic equipment thereof, the laser measurement equipment based on the variable beam light path comprises a light source, the variable beam light path and an objective lens, the diameter of the objective lens is in direct proportion to the numerical aperture of the light source, and the variable beam light path comprises a first collimating mirror and a second collimating mirror. The first collimating lens is located between the second collimating lens and the objective lens, and the focal length of the first collimating lens is smaller than that of the second collimating lens. According to the technical scheme of the embodiment, the focal length ratio of the variable beam light path can be used as a reduction coefficient of the focal length of the objective lens, so that the focal length of the objective lens is reduced under the condition that the diameter of the objective lens is not changed, and the focal length ratio of the variable beam light path can amplify the distance change amplitude of a focus point in the focusing process, so that the object point adjusting distance required by focusing is reduced, and the focusing efficiency is improved. The internal structure of laser measurement equipment is simplified, and the cost is reduced.

Description

Technical Field

[0001] The invention belongs to the field of optical technology, and in particular relates to a laser measuring device based on a variable beam optical path and electronic equipment thereof. Background Art

[0002] Lidar is a radar system that emits laser beams to detect the position, speed and other characteristic quantities of a target. It is commonly used in the fields of laser wind measurement, laser ranging, laser scanning, etc. The working principle of Lidar is to emit a detection signal (laser beam) to the target, and then compare the received signal reflected from the target (target echo) with the transmitted signal. After appropriate processing, relevant information about the target can be obtained, such as target distance, direction, height, speed, attitude, and even shape parameters.

[0003] A common laser radar is composed of a laser transmitter, an optical receiver, a turntable and an information processing system. In the optical components of the laser transmitter, the numerical aperture of the objective lens is limited by the light source, which is usually the optical fiber numerical aperture. If a large-aperture objective lens is configured to achieve high resolution, the focal length of the large-aperture objective lens is long, which increases the size of the overall equipment and makes it difficult to maintain the mechanical stability of the optical path. Moreover, the object point distance that needs to be adjusted for focusing is too large, resulting in the internal structure of the laser measurement equipment being complex, large, and costly, and difficult to implement. Summary of the invention

[0004] The embodiment of the present invention provides a laser measuring device based on a variable beam optical path and an electronic device thereof, which can shorten the focal length of an objective lens, reduce the object point adjustment distance required for focusing, simplify the internal structure of the laser measuring device, and reduce costs.

[0005] In a first aspect, an embodiment of the present invention provides a laser measurement device based on a variable beam optical path, comprising:

[0006] A light source, a beam-changing optical path and an objective lens, wherein the diameter of the objective lens is proportional to the numerical aperture of the light source, the beam-changing optical path comprises a first collimator and a second collimator, the first collimator is located between the second collimator and the objective lens, the focal length of the first collimator is smaller than the focal length of the second collimator, and the focal length and diameter of the objective lens satisfy the following relationship:

[0007] Among them, F 0 is the focal length of the objective lens, F 1 is the focal length of the first collimator, F 2 is the focal length of the second collimator, D is the diameter of the objective lens, and NA is the numerical aperture of the light source.

[0008] According to some embodiments of the present invention, a focusing device is further included, wherein the focusing device is used to drive the light source and the beam-changing optical path to move.

[0009] According to some embodiments of the present invention, the light source includes a laser, a circulator and a detector, the circulator is located between the laser and the beam-changing optical path, the detector is located on the side of the circulator, and the detection direction of the detector is perpendicular to the emission direction of the laser.

[0010] According to some embodiments of the present invention, an intrinsic reference signal lighting mechanism is further included. The intrinsic reference signal lighting mechanism is located between the light source and the beam-changing optical path. The intrinsic reference signal lighting mechanism is used to collect reference light. The reference light interferes with the signal light of the light source in the intrinsic reference signal lighting mechanism to obtain output light.

[0011] According to some embodiments of the present invention, the light-emitting side of the intrinsic reference signal lighting mechanism is an intrinsic reference signal reflecting surface, and the intrinsic reference signal reflecting surface and the end face of the signal light satisfy the following relationship:

[0012] Wherein, rl is the proportion of the reference light in the output light, Re is the reflectivity of the end face of the signal light, θ 1 is the angle between the intrinsic reference signal reflection surface and the end face of the signal light, and σ is the numerical aperture of the optical fiber.

[0013] According to some embodiments of the present invention, a refraction scanning system is further included, and the refraction scanning system is located at the rear end of the objective lens.

[0014] According to some embodiments of the present invention, the refractive scanning system is provided with a rotatable refractive wedge mirror, and the refractive wedge mirror is used to shift the output light spot of the objective lens into a scanning light spot, and the scanning light spot satisfies the following relationship:

[0015] R=L×tanθ 2 , where θ 2 is the offset angle of the scanning spot, R is the offset distance of the scanning spot relative to the center line, and L is the distance between the scanning point of the scanning spot and the objective lens.

[0016] According to some embodiments of the present invention, a photoelectric detection system and a signal processing system are further included. The photoelectric detection system is located at the rear end of the refraction scanning system, and the signal processing system is located at the rear end of the photoelectric detection system.

[0017] In a second aspect, an embodiment of the present invention further provides a laser measurement device, including the laser measurement device based on a variable beam optical path as described in the first aspect.

[0018] The embodiment of the present invention includes: a light source, a beam-changing optical path and an objective lens, wherein the diameter of the objective lens is proportional to the numerical aperture of the light source, the beam-changing optical path includes a first collimator and a second collimator, the first collimator is located between the second collimator and the objective lens, and the focal length of the first collimator is smaller than the focal length of the second collimator. According to the technical solution of this embodiment, the focal length ratio of the beam-changing optical path can be used as a reduction coefficient of the focal length of the objective lens, thereby reducing the focal length of the objective lens while keeping the diameter of the objective lens unchanged. During the focusing process, the focal length ratio of the beam-changing optical path can amplify the distance variation of the focal point, thereby reducing the object point adjustment distance required for focusing, simplifying the internal structure of the laser measurement device, and reducing the cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic structural diagram of a laser measurement device based on a variable beam optical path provided by an embodiment of the present invention;

[0020] Figure 2 is a schematic diagram of the focal length of an objective lens in the prior art;

[0021] Figure 3 is a schematic diagram of the focal length of an objective lens provided by another embodiment of the present invention;

[0022] Figure 4 It is a schematic diagram of focusing distance in the prior art;

[0023] Figure 5 is a schematic diagram of a focusing distance provided by another embodiment of the present invention;

[0024] Figure 6 is a schematic diagram of an intrinsic reference signal reflection surface provided by another embodiment of the present invention;

[0025] Figure 7 It is a refraction schematic diagram of a refraction scanning system provided by another embodiment of the present invention.

[0026] Description of reference numerals:

[0027] 1 laser; 2 circulator; 3 detector; 4 intrinsic reference signal light collection mechanism; 41 intrinsic reference signal reflection surface; 5 second collimator; 6 first collimator; 7 objective lens; 8 refraction scanning system. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0029] It should be noted that, although the functional modules are divided in the device schematic diagram and the logical order is shown in the flowchart, in some cases, the steps shown or described may be performed in a different order than the module division in the device or the order in the flowchart. The terms "first", "target" and the like in the specification, claims or the above drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0030] The present invention provides a laser measuring device based on a variable beam optical path and an electronic device thereof. The laser measuring device based on the variable beam optical path includes: a light source, a variable beam optical path and an objective lens, the diameter of the objective lens is proportional to the numerical aperture of the light source, the variable beam optical path includes a first collimator and a second collimator, the first collimator is located between the second collimator and the objective lens, and the focal length of the first collimator is smaller than the focal length of the second collimator. According to the technical solution of this embodiment, the focal length ratio of the variable beam optical path can be used as a reduction coefficient of the focal length of the objective lens, thereby reducing the focal length of the objective lens while keeping the diameter of the objective lens unchanged. In the process of focusing, the focal length ratio of the variable beam optical path can amplify the distance variation of the focus point, thereby reducing the object point adjustment distance required for focusing, simplifying the internal structure of the laser measuring device, and reducing costs.

[0031] Reference Figures 1 to 3 , the laser measurement device based on the variable beam optical path provided in this embodiment includes:

[0032] A light source, a beam-changing optical path and an objective lens 7, wherein the diameter of the objective lens 7 is proportional to the numerical aperture of the light source, the beam-changing optical path comprises a first collimator 6 and a second collimator 5, the first collimator 6 is located between the second collimator 5 and the objective lens 7, the focal length of the first collimator 6 is smaller than the focal length of the second collimator 5, and the focal length and diameter of the objective lens 7 satisfy the following relationship:

[0033] Among them, F 0 is the focal length of objective lens 7, F 1 is the focal length of the first collimator 6, F 2 is the focal length of the second collimator 5, D is the diameter of the objective lens 7, and NA is the numerical aperture of the light source.

[0034] It should be noted that, in order to fully illuminate the aperture of the objective lens 7, the focal length of the objective lens 7 is the numerical aperture of the objective lens 7, and therefore the focal length of the objective lens 7 is determined by the numerical aperture NA of the light source, such as Figure 2 As shown, Figure 2 is a schematic diagram of the focal length of the objective lens 7 in the prior art, the focal length of the objective lens 7 In this embodiment, a beam-changing optical path is added between the light source and the objective lens 7. The beam-changing optical path is a collimating and converging system composed of a first collimating lens 6 and a second collimating lens 5. The beam-changing optical path changes the divergence angle of the light source through lens collimation and convergence, and fully illuminates the larger objective lens 7 at a shorter focal length to adapt to the large numerical aperture objective lens 7. Figure 3 As shown, the focal length relationship of the objective lens 7 is Since the focal length of the first collimator 6 is smaller than the focal length of the second collimator 5, The optical path can shorten the focal length F while keeping the diameter D the same.

[0035] In addition, in one embodiment, a focusing device is also included, and the focusing device is used to drive the light source and the beam-changing optical path to move.

[0036] It should be noted that the focusing device is used to drive the light source and the beam-changing optical path to move, so that the light source and the moving pipeline can be close to or away from the objective lens 7, thereby achieving the effect of focusing. The specific structure of the focusing device can be selected according to actual needs. This embodiment does not involve the improvement of the focusing device. The focusing device is only used to synchronously adjust the movement of the driving light source and the beam-changing optical path.

[0037] It is worth noting that after introducing the variable beam optical path, the laser measurement device of this embodiment greatly reduces the object point moving distance required for focusing of the objective lens 7 compared with the prior art, and can be achieved by moving a lightweight converging lens.

[0038] For example, Figure 4 As shown, Figure 4 is a schematic diagram of the focusing distance in the prior art, where the object distance between the objective lens 7 and the light source before adjustment is W 0 , the distance between the images formed by the objective lens 7 is L 0 To achieve an image distance from L 0 To adjust the focus from W to L, the object distance needs to be adjusted accordingly. 0 Adjust to W, approximate by the ideal lens formula, when the numerical aperture of the light source is NA, the expression of the object distance movement is: D = 100mm, NA = 0.125, L 0 =50, L=200, change the focal point from 50m to 200m, and the light source movement amount is ΔW=2.4mm.

[0039] For example, Figure 5 As shown, Figure 5 This is a schematic diagram of the focus adjustment distance after the variable beam optical path is introduced in this application. After the variable beam optical path is added, the first collimator 6 is adjusted from Figure 5 The solid line position shown in is moved to the dotted line position, and the expression of the object distance movement is updated as follows: It can be seen that compared with Figure 4 In the example of the prior art shown, an additional because Therefore, in the same focusing process, the object distance will be reduced. For example, ΔW = 0.6 mm, which is shortened to 1 / 4 of the previous value.

[0040] In addition, in one embodiment, reference Figure 1 The light source includes a laser 1, a circulator 2 and a detector 3. The circulator 2 is located between the laser 1 and the beam-changing optical path. The detector 3 is located on the side of the circulator 2. The detection direction of the detector 3 is perpendicular to the emission direction of the laser 1.

[0041] It should be noted that the light source of this embodiment is a laser 1, which is located on the light incident side of a circulator 2. The laser emitted by the laser 1 enters the beam-changing optical path through the circulator 2. At the same time, a detector 3 is arranged on the side of the circulator 2, and the detection direction of the detector 3 is perpendicular to the light emitting direction of the laser 1.

[0042] It should be noted that, when the laser measuring device is a laser wind measuring radar, the weak signal light scattered back by airborne suspended matter is generally mixed with the stronger local oscillator reference light drawn from the light source on the light detector 3 for interference. The Doppler frequency shift of the signal light caused by the movement of the suspended matter can be realized by measuring the beat frequency spectrum output by the light detector 3. Therefore, in this embodiment, the detector 3 is set at the light source to facilitate the realization of laser wind measurement.

[0043] In addition, in one embodiment, referring to Figure 1 , and also includes an intrinsic reference signal lighting structure 4, which is located between the light source and the beam-changing optical path. The intrinsic reference signal lighting structure 4 is used to collect reference light, and the reference light and the signal light of the light source interfere in the intrinsic reference signal lighting structure 4 to obtain output light.

[0044] It should be noted that in order to ensure that the reference light and the signal light have the same optical path in the optical fiber that changes the polarization state, and the polarization states change synchronously, thereby maintaining consistency, the present embodiment sets an intrinsic reference signal lighting structure 4 at the rear end of the light source as a spatial optical path. The reference light is collected by the intrinsic reference signal lighting structure 4, so that the propagation difference between the reference light and the signal light is only in the free space where the polarization state is not changed, while the optical path is the same in the optical fiber that changes the polarization state, so the polarization states change synchronously and cancel each other out, thereby achieving fully coherent output light.

[0045] In addition, in one embodiment, referring to Figure 1 and Figure 6 The light-emitting side of the intrinsic reference signal light-collecting structure 4 is the intrinsic reference signal reflecting surface 41. The intrinsic reference signal reflecting surface 41 and the end surface of the signal light satisfy the following relationship:

[0046] Among them, rl is the proportion of reference light in the output light, Re is the reflectivity of the end face of the signal light, θ 1is the angle between the intrinsic reference signal reflection surface 41 and the end face of the signal light, and σ is the numerical aperture of the optical fiber.

[0047] It should be noted that in order to achieve complete correlation between the reference light and the signal light, it is necessary to control the proportion of the reference light in the output light. According to the above relationship, θ 1 is the angle between the intrinsic reference signal reflection surface 41 and the end face of the signal light, σ is the numerical aperture of the optical fiber. Since the numerical aperture of the optical fiber is a fixed value, it generally satisfies σ∈[0.1,0.3], so the controllable parameter is θ 1 And Re are used to realize the adjustment of rl, ensuring that the polarization states of the reference light and the signal light are consistent and achieving complete interference.

[0048] For example, Figure 6 As shown, the end face of the signal light is Figure 6 The dotted plane shown in FIG. 4 is an inclined plane, and the angle between the two is θ 1 θ can be achieved by controlling the inclination of the intrinsic reference signal reflection surface 41 1 adjustments.

[0049] In addition, in one embodiment, referring to Figure 1 and Figure 7 , also includes a refraction scanning system 8, which is located at the rear end of the objective lens 7.

[0050] It should be noted that a refraction scanning system 8 is provided at the rear end of the objective lens 7. The refraction scanning system 8 can rotate, and a single system can be used to measure in different directions. Combined with the focusing capability, the output light spot of the objective lens 7 is refracted into a scanning light spot, so that the light spot can move in three-dimensional space, thereby realizing scanning measurement.

[0051] In addition, in one embodiment, referring to Figure 1 and Figure 7 The refraction scanning system 8 is provided with a rotatable refraction wedge mirror, which is used to shift the output light spot of the objective lens 7 into a scanning light spot, and the scanning light spot satisfies the following relationship:

[0052] R=L×tanθ 2 , where θ 2 is the offset angle of the scanning spot, R is the offset distance of the scanning spot relative to the center line, and L is the distance between the scanning point of the scanning spot and the objective lens 7.

[0053] It should be noted that, according to the description of the above embodiment, the refractive scanning system 8 can be rotated to move the focal point in three-dimensional space. In this embodiment, a rotatable refractive wedge mirror is arranged in the refractive scanning system 8, and the above effect is achieved by rotating the refractive wedge mirror.

[0054] It should be noted that if Figure 7 As shown, Figure 7 The dotted line in the figure shows the schematic diagram of the position of the output light spot when there is no refractive scanning system 8, and the solid line shows the schematic diagram of the position of the scanning light spot when the refractive scanning system 8 is added. The output light spot of the objective lens 7 enters the refractive wedge mirror and is refracted into a scanning light spot. The offset distance between the scanning light spot and the center line of the light source is R, and the offset angle is θ. 2 , the distance between the scanning point of the scanning spot and the objective lens 7 is L, and the three satisfy the relationship: R = L × tanθ 2 By adjusting the rotation angle and the refraction angle, scanning at any angle of 0-360° can be achieved. At the same time, scanning at any offset distance from the center spot can also be achieved.

[0055] In addition, in one embodiment, a photoelectric detection system and a signal processing system are also included.

[0056] It should be noted that the photoelectric detection system and the signal processing system can compare the signal reflected from the scanning spot obtained in the above embodiment with the transmitted signal, thereby obtaining parameters such as target distance, azimuth, altitude, speed, posture, and even shape. Those skilled in the art are familiar with how to set up the photoelectric detection system and the signal processing system, and will not elaborate on them here.

[0057] In addition, an embodiment of the present invention further provides an electronic device, including the laser measurement device based on the variable beam optical path as described above.

[0058] It should be noted that the laser measuring device may be a laser radar, a laser distance measuring device and a laser scanning device, and the electronic device may be any device equipped with the above laser measuring device, and no limitation is made here. By adopting the above laser measuring device in the electronic device, the focal length ratio of the variable beam optical path can be used as the reduction coefficient of the focal length of the objective lens 7, thereby reducing the focal length of the objective lens 7 while keeping the diameter of the objective lens 7 unchanged. In the process of focusing, the focal length ratio of the variable beam optical path can amplify the distance variation of the focal point, thereby reducing the object point adjustment distance required for focusing, simplifying the internal structure of the laser measuring device, and reducing the cost.

[0059] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the embodiments disclosed herein. The present application is intended to cover any variations, uses or adaptations of the present application, which follow the general principles of the present application and include common knowledge or customary technical means in the art that are not disclosed in the present application.

[0060] It should be understood that the present application is not limited to the precise structures that have been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present application is limited only by the appended claims.

[0061] The above is a specific description of the preferred implementation of the present invention, but the present invention is not limited to the above-mentioned implementation mode. Technical personnel familiar with the field can also make various equivalent deformations or substitutions without violating the spirit of the present invention. These equivalent deformations or substitutions are all included in the scope defined by the claims of the present invention.

Claims

1. A laser measurement device based on a variable beam optical path, characterized in that: include: A light source, a beam-changing optical path and an objective lens, wherein the diameter of the objective lens is proportional to the numerical aperture of the light source, the beam-changing optical path comprises a first collimator and a second collimator, the first collimator is located between the second collimator and the objective lens, the focal length of the first collimator is smaller than the focal length of the second collimator, and the focal length and diameter of the objective lens satisfy the following relationship: Among them, F0 is the focal length of the objective lens, F1 is the focal length of the first collimator, F2 is the focal length of the second collimator, D is the diameter of the objective lens, and NA is the numerical aperture of the light source.

2. The laser measurement device based on a variable beam optical path according to claim 1, characterized in that: It also includes a focusing device, which is used to drive the light source and the beam-changing optical path to move.

3. The laser measurement device based on a variable beam optical path according to claim 1, characterized in that: The light source comprises a laser, a circulator and a detector. The circulator is located between the laser and the beam-changing optical path. The detector is located on the side of the circulator. The detection direction of the detector is perpendicular to the emission direction of the laser.

4. The laser measurement device based on a variable beam optical path according to any one of claims 1 to 3, characterized in that: It also includes an intrinsic reference signal lighting mechanism, which is located between the light source and the beam-changing optical path. The intrinsic reference signal lighting mechanism is used to collect reference light, and the reference light and the signal light of the light source interfere in the intrinsic reference signal lighting mechanism to obtain output light.

5. The laser measurement device based on variable beam optical path according to claim 4, characterized in that: The light-emitting side of the intrinsic reference signal lighting mechanism is an intrinsic reference signal reflection surface, and the intrinsic reference signal reflection surface and the end surface of the signal light satisfy the following relationship: Wherein, rl is the proportion of the reference light in the output light, Re is the reflectivity of the end face of the signal light, θ1 is the angle between the intrinsic reference signal reflection surface and the end face of the signal light, and σ is the numerical aperture of the optical fiber.

6. The laser measurement device based on a variable beam optical path according to any one of claims 1 to 3, characterized in that: It also includes a refraction scanning system, which is located at the rear end of the objective lens.

7. The laser measurement device based on a variable beam optical path according to claim 6, characterized in that: The refractive scanning system is provided with a rotatable refractive wedge mirror, and the refractive wedge mirror is used to shift the output light spot of the objective lens into a scanning light spot, and the scanning light spot satisfies the following relationship: R=L×tanθ2, wherein θ2 is the offset angle of the scanning spot, R is the offset distance of the scanning spot relative to the center line, and L is the distance between the scanning point of the scanning spot and the objective lens.

8. The laser measurement device based on variable beam optical path according to claim 7, characterized in that: It also includes a photoelectric detection system and a signal processing system.

9. An electronic device, characterized in that: It comprises a laser measuring device based on a variable beam optical path as described in any one of claims 1 to 8.

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