CN215340303U

CN215340303U - Matrix light source collimation system

Info

Publication number: CN215340303U
Application number: CN202121205362.6U
Authority: CN
Inventors: 孔令豹; 沈晓慧
Original assignee: Fudan University
Current assignee: Fudan University
Priority date: 2021-06-01
Filing date: 2021-06-01
Publication date: 2021-12-28
Anticipated expiration: 2031-06-01

Abstract

The utility model belongs to the technical field of non-imaging optical design, and particularly relates to a matrix light source collimation system. The collimating system comprises a matrix of collimating elements, each collimating element comprising an aspheric lens and a standard lens. The aspherical lens has two aspherical surfaces as a whole, the two aspherical surfaces have different surface type data, and the standard lens is a normal lens. The collimating system is compact in structure, strict in aperture limitation, small in energy loss and good in collimating effect for the collimation of the matrix laser light source, has a high light energy utilization rate, can greatly improve the detection distance of the laser light source, improves the current laser radar ranging effect, and effectively solves the problem that the current laser detection distance is limited seriously.

Description

Matrix light source collimation system

Technical Field

The utility model belongs to the technical field of optical design and measurement, and particularly relates to a matrix light source collimation system.

Background

The ranging type laser radar is a very common instrument, can help people to know the distance of a distant object under the condition of no contact, and is widely applied to the fields of military, intelligent robots and the like. The divergence angle and the energy of the laser beam are important evaluation indexes influencing distance measurement, the divergence angle of the laser beam is reduced, so that the distance which can be detected by the laser beam is longer, the emission power of the laser is increased, the intensity of the reflected light is stronger, and the measurement sensitivity is improved. The matrix light source can well avoid the problem of increasing the upper limit of the energy threshold of the single light source, and the collimation of the matrix light source through the lens group can well improve the detection distance of the light source, so that the method is an important step for improving the detection distance of the laser radar.

The VCSEL light source has a vertical light emitting characteristic, so that a two-dimensional matrix laser light source can be formed, and the VCSEL light source has great advantages in integration degree compared with other laser light sources. However, without the help of any other structure, the divergence angle is large, and long-distance detection is difficult to achieve, so that the use of the laser ranging system is greatly limited, and therefore, a collimation system needs to be specially designed for the laser ranging system to improve the divergence angle and meet the light beam requirement of long-distance detection.

The prior art almost has no collimation on a matrix laser light source, the collimation of an array light source exists mostly, the light sources are arranged linearly in one dimension, and in the collimation process, the whole light source is collimated, so that the whole design process is complicated, the structure is complex, the processing difficulty is high, and the use requirement is high.

SUMMERY OF THE UTILITY MODEL

The utility model aims to design a matrix light source collimation system to solve the problem that the distance measurement of the existing laser radar is limited.

The technical scheme of the utility model is specifically introduced as follows.

A matrix light source collimation system comprises a matrix laser light source and a matrix collimation lens unit; each collimating lens unit is a lens group consisting of an aspheric lens and a standard lens; the aspheric lens is a lens with a center which is rotationally symmetrical and two aspheric surfaces, the two aspheric surfaces are an aspheric incident surface and an aspheric emergent surface respectively, and the two aspheric surfaces have different surface type data; when the array lens is used, the laser light sources in the matrix laser light sources and the collimating lens units in the matrix collimating lens units are in one-to-one correspondence, the centers of the laser light sources and the lens centers of the lens groups are on the same straight line, light rays emitted by the laser light sources reach the aspheric surface emergent surface through the aspheric surface incident surface of the aspheric surface lens, and are collimated and emitted through the standard lens after being collimated by the aspheric surface lens.

In the utility model, the matrix laser light source is a VCSEL matrix light source.

In the utility model, the divergence angle of a single laser light source in the matrix laser light source is between 24 and 25 degrees.

In the utility model, the caliber of the aspheric lens and the standard lens is less than or equal to the distance between the matrix light source single light sources.

In the utility model, after the light passes through the aspheric lens and the standard lens, the emergent light angle is 0-1 degrees.

The utility model fully considers the collimation requirement of laser radar ranging, deeply understands the main reason that the existing laser radar is limited in measuring distance, adopts the aspheric lens to design the collimation lens group, can meet the current requirement of extending the laser radar ranging to the kilometer range, and has the advantages that:

1. the collimating lens matrix is formed by collimating each light source unit of the matrix light source one to one, and the lens matrix formed by the aspheric lens and the standard lens is simple in structure, is paired with the light sources one to one, and is high in utilization efficiency of the light sources;

2. the collimating lens material adopted by the utility model can be selected according to actual requirements, only parameters of the surface type need to be modified, the collimating lens is flexible and changeable, and compared with the collimating lens designed by a reflection method, the collimating lens does not need to be coated with a film, and the manufacturing cost is low;

3. according to the utility model, through ZEMAX optical design software, the collimation result can be observed on the software by constructing a reasonable light source; the collimation system of the matrix light source provided by the utility model has a very outstanding collimation effect on light beams, and can obtain the very outstanding effect only by simple calculation; the standard lens is mainly arranged according to the divergence angle of light rays passing through the aspheric lens, fine adjustment of the surface shape can be performed according to the self-contained optimization function of the ZEMAX, angle adjustment of light rays with different angles is guaranteed, and the collimation effect is achieved. Meanwhile, the distance between the aspheric lens and the standard lens can be adjusted and set by self, and when the distance between the aspheric lens and the standard lens is changed, the surface shape and the caliber of the standard lens are readjusted. When the distance is not changed greatly or is caused by errors generated during installation, the influence on the angle is small;

4. the VCESL light source adopted by the utility model can be made into a two-dimensional matrix due to the unique light-emitting characteristic, so that the light intensity of the detection light beam is enhanced, and meanwhile, the power of the single light source is small, so that the single light source has small damage to human eyes and is suitable for being popularized and used in life;

5. the utility model does not need to arrange a diaphragm, thereby avoiding the waste of energy of the VCSEL light source.

In summary, compared with the existing laser collimating lens, the laser collimating lens only needs a simple combination of an aspheric lens and a standard lens, does not need other structures, has a lens group with rotational symmetry about the center, is simple in structure, can be flexibly and changeably arranged and adjusted according to the light source arrangement mode of a lens matrix, is convenient to calculate, is low in cost, has a prominent collimating effect (24 degrees and <1 degree), utilizes the idea of one-to-one collimation of the light source and the lens, has high utilization efficiency (more than 85 percent) of the light source, and has a simple structure and good caliber control while improving the detection distance of the light source, thereby having important significance for further performance improvement of the laser radar.

Drawings

Fig. 1 is a schematic structural diagram of a matrix light source collimation system of the present invention.

FIG. 2 is a schematic diagram of a lens matrix unit structure according to an embodiment of the utility model.

FIG. 3 is a ZEMAX ray trace diagram of a VCSEL matrix single light source collimation process in an embodiment of the utility model.

FIG. 4 is a ZEMAX ray trace diagram of the VCSEL matrix light source collimation process in an example of the present invention.

FIG. 5 is a graph showing the distribution of the radiation intensity of a single light source of a VCSEL matrix light source according to an embodiment of the present invention.

FIG. 6 is a graph showing the distribution of the radiation intensity of a single collimated VCSEL matrix light source in an embodiment of the present invention.

FIG. 7 is a graph of irradiance distribution at a target surface 1000.00mm from a VCSEL matrix light source in an embodiment of the present invention.

FIG. 8 is a graph showing an irradiance distribution of a target surface at a distance of 10000.00mm from a VCSEL matrix light source in an embodiment of the present invention.

In the figure, the reference number is 1-matrix laser light source; 2-aspheric lens, 20-aspheric incident surface, 21-aspheric emergent surface; 3-standard lens, 4-detector surface.

Detailed Description

The utility model is explained in more detail below with reference to specific embodiments and the associated drawings.

Example 1

As shown in fig. 1 and 2, the matrix light source collimation system provided by the present invention includes a lens matrix composed of an aspheric lens 2 and a standard lens 3; the aspheric lens 2 is a central rotationally symmetric lens and has two aspheric surfaces, i.e., an aspheric incident surface 20 and an aspheric exit surface 21, and the two aspheric surfaces have different surface types. The standard lens surface shape was optimized using ZEMAX software. When the matrix laser light source device is used, the laser light sources in the matrix laser light source 1 and the collimating lens units in the matrix collimating lens units are in one-to-one correspondence, the centers of the laser light sources and the lens centers of the lens groups are on the same straight line, light rays emitted by the laser light sources reach the aspheric incident surface 20 of the aspheric lens 2, reach the aspheric emergent surface 21 after being collimated by the aspheric lens, and are collimated and emitted by the standard lens 3. The surface type data of both surfaces of the aspherical surface used in this example are given here respectively:

aspherical incident surface 20:

aspherical incident surface 21:

in this embodiment, the matrix laser light source 1 is a VCSEL matrix light source, which is arranged in a honeycomb shape, the aperture of a single light source is 8 micrometers, and the distance between the light sources is 50 micrometers. Initially, the single light source has a divergence angle of 25 °/24.5 °, with the meridian and sagittal planes being substantially coincident.

In this example, the lens material is acrylic PMMA, and the diameters of the aspheric lens and the standard lens are both 58 micrometers, and the thicknesses thereof are both 3 micrometers.

As shown in fig. 3, in the present embodiment, the process of collimating a single light source of a VCSEL matrix light source by using a collimating system is performed in the optical design software ZEMAX. As shown in fig. 4, the process of collimating the VCSEL matrix light source with the collimating system in the optical design software ZEMAX performs ray tracing.

The light of the VCSEL light source is refracted by the aspheric exit surface 21 and collimated after being expanded to a certain extent by the aspheric entrance surface 20, and then is further collimated by the standard lens 3 and then enters the detector surface 4. Finally, the divergence angle of the emergent ray of the single light source is controlled within 1 degree, the divergence angle of the whole matrix light source is also controlled within 1 degree, and the influence of crosstalk between the light sources is almost avoided.

The detector surface 4 is at a distance of 1000mm and 10000mm from the light source 1. And (3) utilizing ZEMAX to carry out simulation detection on a VCSEL matrix light source consisting of seven honeycomb-shaped single light sources after a collimation system corresponding to the VCSEL matrix light source is assembled. FIGS. 5 and 6 show the irradiance distribution at the target surface at distances of 1000mm and 10000mm from the VCSEL matrix light source, respectively; when the distance is 1000mm, the diameter of the surface 4 of the detector is set to be 60mm, and the detection result shows that the utilization rate of the whole light source energy is high and is 82.9%; when the distance is 10000mm, the diameter of the detector surface 4 is set to 600mm, and the detection result shows that the overall utilization efficiency of the light source is still high, namely 82.3%. Simulation detection at two distances proves that the collimation system designed for the VCSEL matrix light source has a good collimation effect on the light source and high utilization efficiency of the energy of the light source.

In summary, the utility model discloses a matrix light source collimation system, which can collimate a VCSEL matrix light source, can greatly reduce the aperture of a collimation lens, and can collimate a light source 1 to a certain extent only by using one aspheric lens 2 and one standard lens 3. Compared with the prior collimating system, the collimating system has the advantages of small caliber, simple structure, convenient assembly, low cost and high energy utilization efficiency of the light source.

In the embodiments, only specific dimensions of the VCSEL light source, the aspheric lens 2 and the standard spherical mirror 3 are selected for specifically describing the experimental ideas and features of the present invention, which are intended to enable those skilled in the art to understand the contents of the present invention and to implement the present invention accordingly, and the protection scope of the present invention is not limited to the above-mentioned embodiments. Therefore, all equivalent changes or modifications made according to the principles and experimental ideas disclosed by the present invention are within the scope of the present invention.

Claims

1. A matrix light source collimation system, characterized in that it comprises a matrix laser light source (1) and a matrix collimation lens unit; each collimating lens unit is a lens group consisting of an aspheric lens (2) and a standard lens (3); the aspheric lens (2) is a central rotational symmetric lens and is provided with two aspheric surfaces which are an aspheric incident surface (20) and an aspheric emergent surface (21) respectively, and the two aspheric surfaces have different surface type data; when the matrix laser light source device is used, the laser light sources in the matrix laser light sources (1) and the collimating lens units in the matrix collimating lens units are in one-to-one correspondence, the centers of the laser light sources and the lens centers of the lens groups are on the same straight line, light rays emitted by the laser light sources reach the aspheric surface emergent surface (21) through the aspheric surface incident surface (20) of the aspheric surface lens (2), are collimated and emitted through the standard lens (3) after being collimated by the aspheric surface lens.

2. The matrix light source collimation system according to claim 1, characterized in that the matrix laser light source (1) is a VCSEL matrix light source.

3. The matrix light source collimation system according to claim 1, characterized in that the divergence angle of the laser light source units in the matrix laser light source (1) is between 24-25 °.

4. The matrix light source collimation system as recited in claim 1, characterized in that the calibers of the aspheric lens (2) and the standard lens (3) are smaller than or equal to the distance between the single light sources of the matrix light source.

5. The matrix light source collimation system as recited in claim 1, characterized in that the light rays exit at an angle of 0-1 ° after passing through the aspheric lens (2) and the standard lens (3).