A VCSEL one-dimensional laser projection system

Abstract

The present invention discloses a VCSEL one-dimensional line laser projection system, which includes a surface array VCSEL, a one-dimensional line lens, and a receiving screen; the light-emitting point array of the surface array VCSEL is distributed in a long strip shape; the width direction of the surface array VCSEL is in the YZ plane in the rectangular coordinate system, and the length direction is in the XZ plane; the front surface of the one-dimensional line lens is a rotationally symmetric even aspherical surface; the rear surface of the one-dimensional line lens is an even aspherical cylinder surface; the generatrix of the even aspherical cylinder surface is in the XZ plane in the rectangular coordinate system, and the stretching direction is along the Y direction; the light beam emitted by each light-emitting point of the surface array VCSEL is collimated by the rotationally symmetric even aspherical surface, and then undergoes stretching and homogenization in the length direction of the light-emitting point array by the even aspherical cylinder surface, and the light transmission direction in the YZ plane remains unchanged, and finally the one-dimensional line laser is projected onto the receiving screen; the present invention weakens the laser speckle inside the one-dimensional line, improves the quality of the projected one-dimensional line, has a simple structure, low cost, and small volume.

Description

Technical Field

[0001] The present invention relates to a VCSEL one-dimensional line laser projection system, belonging to the technical field of laser beam shaping. Background Art

[0002] With the popularization of structured light, one-dimensional line laser projection systems are increasingly applied to depth detection and 3D perception in the industrial and consumer electronics industries. This requires the one-dimensional line laser to have a narrower width, higher uniformity, and higher brightness. At the same time, the system is becoming more and more miniaturized. Traditional one-dimensional line laser projection systems mostly use single-mode laser diodes (LDs) as the light source for the one-dimensional line. However, due to the good monochromaticity and coherence of the laser, when the light of the LD irradiates the rough surface of a general object, speckles will be formed on the object surface due to light interference, thus generating a granular structure inside the one-dimensional line spot, reducing the quality of the one-dimensional line and directly affecting the calculation results of depth detection and 3D perception. Currently, the one-dimensional line laser projection systems on the market do not propose corresponding solutions for the speckles inside the one-dimensional line.

[0003] A vertical-cavity surface-emitting laser (VCSEL), a semiconductor laser, has an array of light-emitting points distributed on its surface, and its light emits perpendicularly to the top surface. It is a surface-emitting laser. Compared with edge-emitting laser diodes, VCSEL chips have many advantages such as good mode, low threshold current, good stability, long lifespan, high modulation rate, high integration, small divergence angle, high coupling efficiency, and low cost. In addition, using a VCSEL array can reduce the interference between VCSEL lasers, weaken laser speckles, and thus improve the quality of projection display.

[0004] Chinese Patent CN106019620A discloses a device for suppressing laser speckles and a laser projection device. By setting multiple groups of module components with different temperatures of semiconductor lasers in each group, the wavelengths of the same-color lasers output by the semiconductor lasers in each group are different, showing a certain difference, thereby effectively suppressing the laser speckle effect. The main disadvantages of this method are as follows: it requires multiple groups of semiconductor lasers and temperature control devices, resulting in high costs, difficult miniaturization of the volume, and higher requirements for suppressing chromatic dispersion in the optical system for multi-wavelength lasers.

[0005] Chinese Invention Patent CN108873368A discloses a method for suppressing laser speckle and a MEMS micromirror. By optimizing the design of the traditional MEMS micromirror structure, the MEMS micromirror can achieve auxiliary motion (a small translation perpendicular to the mirror surface or a small rotation about the y-axis) while twisting around the torsion axis, reducing the beam coherence while deflecting the incident beam, so as to achieve the function of suppressing laser speckle while meeting the working requirements of the optical system. This method can only be applied to systems containing MEMS micromirrors and has great limitations.

[0006] In the existing one-dimensional laser projection system, the light source is mostly an edge-emitting laser diode, and the projected one-dimensional line spot has a serious speckle effect. There is no specific solution to this problem in the current one-dimensional line projection system. Other speckle suppression solutions are either too costly and difficult to miniaturize in size, or require special components in the optical system itself, with great limitations. Summary of the Invention

[0007] Aiming at the above existing technical problems, the object of the present invention is to propose a VCSEL one-dimensional laser projection system, which has a simple structure, low cost, small size, suppresses the speckle effect of the one-dimensional line spot, and improves the quality of the projected one-dimensional line.

[0008] The technical solution of the present invention is realized as follows: A VCSEL one-dimensional laser projection system includes a surface array VCSEL, a one-dimensional line lens, and a receiving screen; the light-emitting point array of the surface array VCSEL is distributed in a long strip shape; the width direction of the surface array VCSEL is in the YZ plane in the rectangular coordinate system, and the length direction is in the XZ plane; the front surface of the one-dimensional line lens is a rotationally symmetric even aspherical surface; the rear surface of the one-dimensional line lens is an even aspherical cylinder surface; the generatrix of the even aspherical cylinder surface is in the XZ plane in the rectangular coordinate system, and the stretching direction is along the Y direction; the light beam emitted by each light-emitting point of the surface array VCSEL is collimated by the rotationally symmetric even aspherical surface, and then undergoes stretching and homogenization in the length direction of the light-emitting point array by the even aspherical cylinder surface, and the light transmission direction in the YZ plane remains unchanged, and finally the one-dimensional line laser is projected onto the receiving screen.

[0009] Preferably, the generatrix of the even aspherical cylinder surface is consistent with the length direction of the light-emitting point array of the surface array VCSEL.

[0010] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0011] A VCSEL one-dimensional line laser projection system of the present invention uses a planar array VCSEL as the light source of the one-dimensional line laser projection system. By using the planar array VCSEL, the interference between each VCSEL light-emitting point is reduced, the laser speckle inside the one-dimensional line is weakened, and the quality of the projected one-dimensional line is improved. At the same time, no additional speckle reduction device is added to the system, so the structure is simple, the cost is low, and the volume can be made very small. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The technical solution of the present invention will be further described below with reference to the accompanying drawings:

[0013] Attached Figure 1 is a schematic diagram of a VCSEL one-dimensional line laser projection system of the present invention in the YZ plane of a right-handed Cartesian coordinate system;

[0014] Attached Figure 2 is a schematic diagram of a VCSEL one-dimensional line laser projection system of the present invention in the XZ plane of a right-handed Cartesian coordinate system;

[0015] Wherein: 1. Planar array VCSEL; 2. One-dimensional line lens; 3. Receiving screen; 2a. Even aspherical surface; 2b. Even aspherical cylindrical surface. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0016] The present invention will be described below with reference to the accompanying drawings.

[0017] As shown in the attached Figure 1 、 2 , a VCSEL one-dimensional line laser projection system of the present invention includes a planar array VCSEL 1, a one-dimensional line lens 2 and a receiving screen 3; the light-emitting point array of the planar array VCSEL 1 is distributed in a long strip shape, the width direction of the planar array VCSEL 1 is in the YZ plane of the Cartesian coordinate system, and the length direction is in the XZ plane; the front surface of the one-dimensional line lens 2 is a rotationally symmetric even aspherical surface 2a; the rear surface of the one-dimensional line lens 2 is an even aspherical cylindrical surface 2b; the generatrix of the even aspherical cylindrical surface 2b is in the XZ plane of the Cartesian coordinate system, and the stretching direction is along the Y direction, which is consistent with the length direction of the light-emitting point array of the planar array VCSEL 1; during use, the light beam emitted by each light-emitting point of the planar array VCSEL 1 is collimated by the rotationally symmetric even aspherical surface 2a, and then stretched and homogenized in the length direction of the light-emitting point array by the even aspherical cylindrical surface 2b, and the light transmission direction in the YZ plane remains unchanged. Finally, the one-dimensional line laser is projected onto the receiving screen 3.

[0018] The present invention uses a planar array VCSEL1 as the light source of a one-dimensional line laser projection system, and utilizes the planar array VCSEL1 to reduce the interference between each VCSEL light-emitting point, weaken the laser speckle inside the one-dimensional line, and improve the quality of the projected one-dimensional line. At the same time, no additional speckle reduction device is added to the system, which has a simple structure, low cost, and can also be made very small in volume.

[0019] The above embodiments are only for illustrating the technical concept and features of the present invention, and the purpose is to enable those skilled in the art to understand the content of the present invention and implement it. It should not be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.

Claims

1. A VCSEL one-line laser projection system, characterized in that: It includes a planar array VCSEL, a one-dimensional line lens, and a receiving screen; the light-emitting point array of the planar array VCSEL is distributed in a long strip shape; the width direction of the planar array VCSEL is in the YZ plane in the rectangular coordinate system, and the length direction is in the XZ plane; the front surface of the one-dimensional line lens is a rotationally symmetric even aspherical surface; the rear surface of the one-dimensional line lens is an even aspherical cylinder; the generatrix of the even aspherical cylinder is in the XZ plane in the rectangular coordinate system, and the stretching direction is along the Y direction; the light beam emitted by each light-emitting point of the planar array VCSEL is collimated by the rotationally symmetric even aspherical surface, and then undergoes stretching and homogenization in the length direction of the light-emitting point array by the even aspherical cylinder, and the light transmission direction in the YZ plane remains unchanged, and finally the one-dimensional line laser is projected onto the receiving screen; The generatrix of the even aspherical cylinder is consistent with the length direction of the light-emitting point array of the planar array VCSEL.

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