CN115184899A - Ultrashort-focus laser radar and preparation method thereof - Google Patents

Abstract

The invention provides an ultra-short-focus laser radar and a preparation method thereof, wherein the ultra-short-focus laser radar comprises a laser emission component, a mems micro-reflection scanning component and an acquisition component, wherein the laser emission component, the mems micro-reflection scanning component and the acquisition component are arranged in a slit, the walls at two sides of the slit are provided with total reflection interfaces, one of the walls at two sides of the slit is provided with an acquisition window, and the position of the acquisition window does not form a total reflection interface; the laser emission assembly irradiates the mems micro-reflection scanning assembly, scanning laser beams reflected by the mems micro-reflection scanning assembly irradiate the acquisition window through the total reflection interface, and light beams reflected from the acquisition window are incident to the acquisition assembly after being reflected for multiple times. The invention can control the thickness of the laser radar below 1CM, thereby detecting the distribution condition of bubbles or other components in various liquids in real time with little disturbance, and is especially suitable for detecting the distribution condition of bubbles in bubble concrete or detecting internal images of certain narrow positions.

Description

Ultra-short focus laser radar and preparation method

technical field

The invention relates to the field of laser radar, in particular to an ultra-short focus laser radar and a preparation method.

Background technique

MEMS lidar is a radar system that uses a two-dimensional MEMS scanning galvanometer as a scanning mechanism, emits a laser beam to the detection target, receives and processes the echo signal reflected by the detection target, and obtains characteristic information such as the distance, position and speed of the detection target. , has the advantages of small size, high frame rate, low power consumption, and low cost, and is usually used in fields such as autonomous driving, 3D modeling, and terrain mapping. However, existing lidars are usually bulky and inconvenient to use in some special occasions. For example, in the case of scanning the air bubble uniformity in the aerated concrete, the existing air-entrained concrete is usually observed by sampling a cylinder after initial setting, and this detection method easily leads to the loss of the strength of the concrete. Therefore, a device that can detect the uniformity of air bubbles in real time is required, and if the volume of the air bubble detection device is too large, the quality of the air-entrained concrete will also be affected. CN 110488246 A describes a two-dimensional MEMS scanning laser radar signal receiving system with a large field of view. The solution can reduce the volume of the laser radar to a certain extent, but it is still not enough for the detection of aerated concrete.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide an ultra-short-focus laser radar and a preparation method, which can greatly reduce the volume of the laser radar and can accurately detect the uniformity in aerated concrete at a very close distance.

Another technical problem to be solved by the present invention is that the ultra-short focus laser radar can be prepared by a simple method and at a lower cost.

In order to solve the above-mentioned technical problems, the technical solution of the present invention is: an ultra-short focus laser radar, comprising a laser emission component, a mems micro-reflection scanning component and a collection component, and the laser emission component, the mems micro-reflection scanning component and the collection component are arranged on the In the slit, the walls on both sides of the slit are provided with a total reflection interface, and a collection window is provided on one of the walls on both sides of the slit, and the position of the collection window does not form a total reflection interface;

The laser emission component illuminates the mems micro-reflection scanning component, the scanning laser beam reflected by the mems micro-reflection scanning component illuminates the acquisition window through the total reflection interface, and the beam reflected from the acquisition window enters the acquisition component after multiple reflections.

In a preferred solution, in the optical path of the laser beam, the laser beam undergoes at least one reflection before the acquisition window, and the scanned laser beam is gradually dispersed after reflection.

In a preferred solution, at least one reflective concave surface is provided in the optical path behind the acquisition window, so that the scanned laser beam is gradually converged after multiple reflections.

In a preferred solution, the total reflection interface is composed of an inner filling layer and an outer covering layer, and the laser emission component, the mems micro-reflection scanning component and the acquisition component are all placed in the inner filling layer.

In a preferred solution, the total reflection interface is composed of an inner filling layer and an outer covering layer, the acquisition components are all placed in the inner filling layer, and the laser emitting component and the mems micro-reflection scanning component are placed in the bottom of the inner filling layer. intracavity.

In a preferred solution, a light shield is provided on the top of the component cavity near the laser emitting component, and an antireflection coating is provided on the top of the component cavity near the mems micro-reflection scanning component.

In a preferred solution, the laser emitting assembly includes a laser light source and a converging lens arranged in sequence;

The collection assembly includes an optoelectronic assembly and a collection lens assembly arranged in sequence.

A preparation method of the above-mentioned ultra-short focus laser radar, comprising the following steps:

S1. Process two side templates and side templates, fix the acquisition component, the mems micro-reflection scanning component and the laser emission component on the side template, and fix the flexible cable on the side template;

There are positioning pin holes on the side template for fixing the acquisition component, the mems micro-reflection scanning component and the laser emission component. At least one of the side templates is provided with a collection window level for generating a collection window. At least one of the side templates is provided with a collection window. There is a concave surface on it, which is used to generate a reflective concave surface;

Fixed installation bottom template;

mold closing;

S2, pour the components forming the inner filling layer into the mold from the upper mouth, demould after solidification, and shape;

The inner filling layer adopts polymethyl methacrylate, transparent polyurethane or transparent epoxy resin;

S3. Coat the outer covering layer on the finished product after demoulding, and cure the outer covering layer by heating or normal temperature;

The outer cover is polytetrafluoroethylene;

Through the above steps, the preparation of ultra-short-focus lidar is realized.

In a preferred solution, the optoelectronic assembly, the second polarizer and the collecting lens assembly of the collecting assembly are integrated into one component, and at least two fixing pins are arranged on each side of the outer wall of the component, and the fixing pins are inserted into the preset positioning on the side template. in the pin hole;

The laser light source, the first polarizer and the converging lens of the laser emitting assembly are integrated into one component, and at least two fixing pins are arranged on one side of the outer wall of the component, and the fixing pins are inserted into the preset positioning pin holes on the side template;

The two sides of the mems micro-reflection scanning assembly are provided with fixing pins, and the corresponding fixing pins of the mems micro-reflection scanning assembly are installation grooves, and the fixing pins are slid into the installation grooves for positioning;

The side formwork is also provided with a cavity partition groove, which is inclined with the horizontal plane, and is used to insert the cavity partition plate as a bottom formwork to form the inclined top of the component cavity.

In a preferred solution, step s1 further includes the step of arranging a cavity partition plate, and a shading plate is provided on the side of the cavity partition plate facing the collecting assembly, so that the shading plate is pre-buried in the inner filling layer;

The cavity partition plate is roughly perpendicular to the beam reflected by the mems micro-reflection scanning component;

The beam emission angle of the laser emission component is 40°~70°.

The ultra-short-focus laser radar and its preparation method provided by the present invention can control the thickness of the laser radar to be less than 1CM, so that the distribution of bubbles or other components in various liquids can be detected in real time with little disturbance, which is especially suitable for It is used to detect the distribution of air bubbles in air-filled concrete, or to detect certain narrow locations, such as the internal images of certain cavity structures. In the present invention, the ultra-short-focus laser radar can be prepared in a simple method by means of mold processing, which greatly reduces the preparation cost, and can also ensure the equipment precision and improve the preparation efficiency.

Description of drawings

Below in conjunction with accompanying drawing and embodiment, the present invention will be further described:

FIG. 1 is a front view of the present invention.

Figure 2 is a front view of the side formwork of the present invention.

Figure 3 is a side view of the first side formwork of the present invention.

Figure 4 is a side view of the second side formwork of the present invention.

FIG. 5 is a schematic diagram of the collection assembly of the present invention.

In the figure: outer cover layer 1, inner filling layer 2, flexible cable 3, acquisition component 4, optoelectronic component 41, second polarizer 42, acquisition lens component 43, total reflection interface 5, acquisition window 6, mems micro-reflection Scanning assembly 7, shading plate 8, converging lens 9, first polarizer 10, laser light source 11, assembly cavity 12, side template 13, positioning pin hole 14, side mold positioning groove 15, first reflective concave surface 16, second Reflecting concave surface 16 ′, mounting groove 17 , cavity blocking groove 18 , laser emitting assembly 100 , first side template 200 , first concave position 201 , acquisition window level 202 , second side template 300 , second concave position 301 .

Detailed ways

Example 1:

As shown in FIG. 1, an ultra-short-focus laser radar includes a laser emitting component 100, a mems micro-reflection scanning component 7 and a collection component 4, and the laser emitting component 100, the mems micro-reflection scanning component 7 and the collection component 4 are arranged in a slit , the walls on both sides of the slit are provided with a total reflection interface 5, and one of the walls on both sides of the slit is provided with a collection window 6, and the position of the collection window 6 does not form a total reflection interface 5; Out of the laser scanning beam, and into the reflected light. The structure shown in FIG. 1 is only a schematic diagram. In fact, the distance H between the left and right sides in FIG. 1 is 1 cm, the width is 2-3 cm, and the height is 70 cm. The beam emission angle of the laser emission component 100 is 40°˜70°. That is, the angle between the laser beam and the horizontal plane is 40°˜70°, preferably 61°. The mems micro-reflection scanning component 7 is a product of Wuhan Enshuo Technology Co., Ltd., and this application adopts a 400*300 mems micro-reflection mirror array structure.

In a preferred solution, as shown in FIG. 1 , the laser emitting assembly 100 includes a laser light source 11 , a first polarizer 10 and a converging lens 9 arranged in sequence; the laser light source 11 adopts a laser LED.

As shown in FIG. 5 , the collection assembly 4 includes an optoelectronic assembly 41 , a second polarizer 42 and a collection lens assembly 43 arranged in sequence. It is also feasible to use the camera module of the mobile phone with the second polarizer 42 if necessary. Due to the structure of the total reflection interface, the phase of the light beam will not change during the reflection process, and the phase of the first polarizer 10 and the second polarizer 42 are the same. With this structure, the reflected light will not be polluted by stray light, from the collection window 6 Get accurate reflection images. In a preferred solution, it is also feasible to not use the structure of the first polarizer 10 and/or the second polarizer 42 .

As shown in FIG. 1 , the laser emitting assembly 100 illuminates the mems micro-reflection scanning assembly 7, the scanning laser beam reflected by the mems micro-reflection scanning assembly 7 illuminates the acquisition window 6 through the total reflection interface 5, and the beam reflected from the acquisition window 6 undergoes multiple reflections. Incident collection assembly 4 .

A preferred solution is shown in FIG. 1 , in the optical path of the laser beam, the laser beam undergoes at least one reflection before the collection window 6 , and the scanned laser beam is gradually scattered after reflection. With this structure, the scanning beam irradiated to the acquisition window 6 has sufficient optical path spread.

In a preferred solution, as shown in FIG. 1 , at least one reflective concave surface is provided in the optical path behind the acquisition window 6 , so that the scanned laser beam is gradually converged after multiple reflections. If the length of the entire ultra-short-focus lidar is long enough, and one reflective concave surface is sufficient, if the length of the entire ultra-short-focus lidar is short, 2 to 3 reflective concave surfaces can be used, as shown in Figure 1, using the first Structure of the reflective concave surface 16 and the second reflective concave surface 16'.

The preferred solution is shown in FIG. 1 , the total reflection interface 5 is composed of an inner filling layer 2 and an outer covering layer 1 , and the laser emitting component 100 , the mems micro-reflection scanning component 7 and the acquisition component 4 are all placed between the inner filling layer 2 . Inside. The mems micro-reflection scanning component 7 is located in a transparent glass cover.

The preferred solution is as shown in Figure 1, the total reflection interface 5 is composed of an inner filling layer 2 and an outer covering layer 1, the acquisition components 4 are all placed in the inner filling layer 2, the laser emitting component 100 and the mems micro-reflection scanning component 7 is placed in the component cavity 12 at the bottom of the inner filling layer 2 .

In a preferred solution, a light shielding plate 8 is provided on the top of the component cavity 12 close to the laser emitting component 100, and the light shielding plate 8 is used to block the scattered stray light of the laser light source 11, and the top of the component cavity 12 is close to the mems micro-reflection scanning component The position of 7 is provided with an anti-reflection coating, whereby the structure reduces the light reflectivity at the top of the component cavity 12 . The bottom of the assembly cavity 12 is closed.

Taking the detection of bubble concrete as an example, when in use, insert the lower end of the ultra-short focus laser radar into the bubble concrete that has not yet set at a constant speed, and the laser beam emitted by the laser emitting component 100 scans the acquisition window 6 through the mems micro-reflection scanning component 7, The laser beam is reflected from the position of the acquisition window 6 to the acquisition component 4, and the images obtained by scanning are stitched together to obtain the bubble distribution at the position, so as to avoid the phenomenon of delamination of the bubbled concrete. In a preferred solution, through laser ranging, the solution of the present invention can also be used to detect the surface morphology of the narrow cavity position based on the point cloud difference, that is, the distance difference between the surface point cloud and the depth point cloud.

Example 2:

A preparation method of the above-mentioned ultra-short focus laser radar, comprising the following steps:

S1. Process the two side templates 13 as shown in Fig. 2 and the first side template 200 and the second side template 300 as shown in Figs. On the side formwork 13, fix the flexible flat cable 3 on the side formwork;

The side template 13 is provided with positioning pin holes 14 for fixing the acquisition component 4, the mems micro-reflection scanning component 7 and the laser emission component 100, wherein there are at least two positioning pin holes 14 on each side of the corresponding acquisition component 4, at least one of them The side template is provided with a collection window level 202, and the collection window level 202 is embodied as a rectangular groove on the first side template 200, so that the inner filling layer 2 forms a window structure here. Used to generate acquisition window 6. At least one edge template is provided with a concave surface for generating a reflective concave surface; in this example, a first concave surface 201 is set on the first edge template 200, and a second concave surface 301 is set on the second edge template 300. In the scheme, the first concave position 201 and the second concave position 301 are both located on the reflected light path of the laser beam.

The bottom formwork is fixedly installed; preferably, the side formwork 13 is further provided with a cavity partition groove 18, and the cavity partition groove 18 is inclined to the horizontal plane for inserting the cavity partition plate as the bottom formwork to form the inclined top of the component cavity 12.

Clamp the mold, insert the first side template 200 and the second side template 300 into the side mold positioning slot 15, insert the cavity partition plate into the cavity partition slot 18, install the acquisition component 4, the mems micro-reflection scanning component 7 and The laser emitting assembly 100 completes the mold clamping operation;

S2, pour the components forming the inner filling layer 2 into the mold from the upper mouth, demould after solidification, and shape;

The inner filling layer 2 is made of polymethyl methacrylate, transparent polyurethane or transparent epoxy resin; in this example, transparent epoxy resin is preferably used, and the transparent epoxy resin is cured by ultraviolet light. After demoulding, remove the positioning pin, rest the position where the edge is not smooth, and place the collection window 6 to block the sticking of the adhesive strip. Paraffin wax is preferably used as the mold release agent.

S3, coating the outer covering layer 1 on the finished product after demoulding, and curing the outer covering layer 1 by heating or normal temperature;

The outer cover layer 1 is made of polytetrafluoroethylene; preferably, a polytetrafluoroethylene slurry is used to coat the outside of the inner filling layer 2 . It is cured by heating at a temperature of 90 degrees Celsius. A total reflection interface 5 is formed between the transparent outer cover layer 1 and the inner filling layer 2 .

Through the above steps, the preparation of ultra-short-focus lidar is realized.

In a preferred solution, the optoelectronic component 41 , the second polarizer 42 and the collection lens component 43 of the collecting component 4 are integrated into one component, and at least two fixing pins are provided on each side of the outer wall of the component, and the fixing pins are inserted into the side template 13 in the preset positioning pin hole 14;

The laser light source 11 , the first polarizer 10 and the converging lens 9 of the laser emitting assembly 100 are integrated into one component, at least two fixing pins are arranged on one side of the outer wall of the component, and the fixing pins are inserted into the preset positioning pins on the side template 13 in hole 14;

The two sides of the mems micro-reflection scanning assembly 7 are provided with fixing pins. The fixing pins of the mems micro-reflection scanning assembly 7 correspond to the mounting grooves 17. The fixing pins are slid into the mounting grooves 17 for positioning; in this example, about 500 After the second time, the position of the acquisition window 6 will be damaged due to wear and tear, and the relatively expensive mems micro-reflection scanning assembly 7 can be taken out and replaced for reuse. to save equipment costs.

In a preferred solution, step s1 further includes the step of arranging a cavity partition plate, and a shading plate 8 is provided on the side of the cavity partition plate facing the collection assembly 4, so as to pre-embed the shading plate 8 in the inner filling layer 2;

The cavity partition plate is roughly perpendicular to the beam reflected by the mems micro-reflection scanning component 7;

The beam emission angle of the laser emission component 100 is 40°˜70°. Preferably it is 61°.

The above-mentioned embodiments are only the preferred technical solutions of the present invention, and should not be regarded as limitations of the present invention. The embodiments and features in the present application may be arbitrarily combined with each other without conflict. The protection scope of the present invention shall take the technical solutions described in the claims, including the equivalent alternatives of the technical features in the technical solutions described in the claims, as the protection scope. That is, equivalent replacements and improvements within this scope are also within the protection scope of the present invention.

Claims (10)

1. An ultra-short-focus laser radar is characterized in that: the slit laser scanning device comprises a laser emitting component (100), a mems micro-reflection scanning component (7) and a collecting component (4), wherein the laser emitting component (100), the mems micro-reflection scanning component (7) and the collecting component (4) are arranged in a slit, the walls of two sides of the slit are provided with total reflection interfaces (5), a collecting window (6) is arranged on one wall of two sides of the slit, and the total reflection interfaces (5) are not formed at the position of the collecting window (6);

the laser emitting assembly (100) irradiates the mems micro-reflection scanning assembly (7), scanning laser beams reflected by the mems micro-reflection scanning assembly (7) irradiate the acquisition window (6) through the total reflection interface (5), and light beams reflected from the acquisition window (6) are reflected for multiple times and then enter the acquisition assembly (4).

2. Ultra-short focus lidar according to claim 1, wherein: in the light path of the laser beam, the laser beam is reflected at least once before the collection window (6), and the scanned laser beam is gradually dispersed after reflection.

3. An ultra-short-focus lidar according to claim 2, wherein: at least one reflection concave surface is arranged in a light path behind the collection window (6) so that the scanned laser beam is gradually folded after being reflected for multiple times.

4. An ultra-short-focus lidar according to claim 3, wherein: the total reflection interface (5) consists of an inner filling layer (2) and an outer covering layer (1), and the laser emitting component (100), the mems micro-reflection scanning component (7) and the acquisition component (4) are all arranged in the inner filling layer (2).

5. An ultra-short-focus lidar according to claim 3, wherein: the total reflection interface (5) consists of an inner filling layer (2) and an outer covering layer (1), the acquisition component (4) is completely arranged in the inner filling layer (2), and the laser emission component (100) and the mems micro-reflection scanning component (7) are arranged in a component cavity (12) at the bottom of the inner filling layer (2).

6. An ultra-short-focus lidar according to claim 5, wherein: a shading plate (8) is arranged at the position, close to the laser emission assembly (100), of the top of the assembly cavity (12), and a reflection reducing coating is arranged at the position, close to the mems micro-reflection scanning assembly (7), of the top of the assembly cavity (12).

7. Ultra short-focus lidar according to claim 4 or 5, wherein: the laser emitting assembly (100) comprises a laser light source (11) and a converging lens (9) which are sequentially arranged;

the acquisition assembly (4) comprises a photoelectric assembly (41) and an acquisition lens assembly (43) which are sequentially arranged.

8. A preparation method of the ultra-short-focus laser radar as claimed in any one of claims 1 to 7, which is characterized by comprising the following steps:

s1, processing two side templates (13) and side templates, fixing a collection assembly (4), a mems micro-reflection scanning assembly (7) and a laser emission assembly (100) on the side templates (13), and fixing a flexible flat cable (3) on the side templates;

the side templates (13) are provided with positioning pin holes (14) for fixing the acquisition assembly (4), the mems micro-reflection scanning assembly (7) and the laser emission assembly (100), at least one of the side templates is provided with an acquisition window position (202) for generating an acquisition window (6), and at least one of the side templates is provided with a concave surface position for generating a reflection concave surface;

fixedly mounting a bottom template;

closing the mold;

s2, pouring the components for forming the inner filling layer (2) into a mold from an upper opening, demolding after solidification, and shaping;

the inner filling layer (2) is made of polymethyl methacrylate, transparent polyurethane or transparent epoxy resin;

s3, coating the outer covering layer (1) on the demoulded finished product, and heating or curing the outer covering layer (1) at normal temperature;

the outer covering layer (1) is made of polytetrafluoroethylene;

the preparation of the ultra-short-focus laser radar is realized through the steps.

9. The method for preparing an ultra-short-focus lidar according to claim 8, wherein the method comprises: the photoelectric component (41), the second polarizer (42) and the collection lens component (43) of the collection component (4) are integrated into a component, at least two fixing pins are arranged on each side of the outer wall of the component, and the fixing pins are inserted into positioning pin holes (14) preset in the side template (13);

a laser light source (11), a first polarizer (10) and a converging lens (9) of a laser emitting assembly (100) are integrated into one component, at least two fixing pins are arranged on one side of the outer wall of the component, and the fixing pins are inserted into positioning pin holes (14) preset in a side template (13);

fixing pins are arranged on two sides of the mems micro-reflection scanning assembly (7), mounting grooves (17) correspond to the fixing pins of the mems micro-reflection scanning assembly (7), and the fixing pins slide into the mounting grooves (17) for positioning;

the side die plate (13) is also provided with a cavity partition groove (18), and the cavity partition groove (18) is inclined to the horizontal plane and used for inserting a cavity partition plate as a bottom die plate to form an inclined top of the module cavity (12).

10. The method for preparing an ultra-short-focus lidar according to claim 8, wherein the method comprises: step s1, a cavity partition plate is arranged, wherein a light screen (8) is arranged on one side of the cavity partition plate facing the acquisition assembly (4) so as to pre-embed the light screen (8) in the inner filling layer (2);

the cavity partition plate is approximately vertical to the light beam reflected by the mems micro-reflection scanning assembly (7);

the light beam emission angle of the laser emission assembly (100) is 40-70 degrees.

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