Reflection-type homogenizing mirror for generating flat-top-like rectangular light spots and homogenizing system

Abstract

The invention discloses a reflection type homogenizing mirror for generating flat-top-like rectangular light spots and a homogenizing system, and belongs to the field of laser processing. The reflection type homogenizing mirror for generating flat-top-like rectangular light spots comprises a mirror body and a reflection mirror surface, the reflection mirror surface comprises a left rotating curved surface set and a right rotating curved surface set, the distance fw between the rotating curved surface sets and a working face, the vertical distances hl and hr between the rotating curved surface sets and respective rotating shafts, and the distances dl and dr between the left rotating shaft and the right rotating shaft and the central axis of the two rotating curved surface sets meet the relations shown in the following formulas, uniform-like light spots can be obtained in the uniform-like direction, D1 is the left half width of incident light on the reflecting mirror surface, and Dr is the right half width of the incident light on the reflecting mirror surface. The light spot edge in the quasi-uniform direction drops steeply, so that the virtual light influence caused by Gaussian distribution can be greatly reduced, the utilization rate of Gaussian beam edge energy is effectively improved, and the application range is wider. According to the device, a high-precision rotating lathe can be adopted for machining, an expensive high-precision free-form surface machining machine tool is not needed, and the machining cost can be reduced.

Description

technical field [0001] The invention relates to the field of laser processing, and more specifically, to a reflective homogenization mirror and a homogenization system for generating a flat-topped rectangular spot. Background technique [0002] The uniform flat-top rectangular spot is widely used in the field of laser processing. The uniform flat-top rectangular spot can obtain very precise processing effects in laser processing. For example, laser surface modification systems such as laser phase change quenching and laser cladding require more Uniform flat-topped rectangular spot. [0003] In the prior art, there are many methods for shaping and homogenizing laser beams, such as microlens arrays, diffractive optical elements, reflective array integrators, and the like. The cost of the microlens array is high, and there are requirements on the wavelength of the light source, and because it is a transmissive optical element, it cannot be used for high-power laser processing;...

AI Technical Summary

Problems solved by technology

The cost of the microlens array is high, and there are requirements on the wavelength of the light source, and because it is a transmissive optical element, it cannot be used for high-power laser processing; the diffractive optical element can shape the laser Gaussian beam into a more uniform energy spot, but the diffractive optical element requires Using a single-mode laser light source, and accurately knowing the amplitude and phase distribution of the light source, the diffractive optical element has poor anti-misalignment characteristics and poor flexibility

In addition, as a transmissive optical element, the laser power it can bear is limited

[0004] At present, the practically applied homogenizing mirror is mainly a reflective integrator mirror, which is processed by copper substrate, and can be designed with a water cooling method on the back, which can be used for high-power laser applications. The traditional reflective integrator mirror can only achieve uniform energy distribution in one direction, and in the other The energy in one direction has a Gaussian distribution, and the uniformity in the direction of the Gaussian energy distribution is greatly affected by the light source and collimation conditions. Because the Gaussian edge part cannot reach the processing threshold of the material, a kind of virtual light is formed, which greatly reduces the laser beam. effective utilization

II-VI Corporation of the United States has launched a reflective array integrator mirror, which can solve the problem of homogenization in two directions, but this mirror is a free-form mirror, which needs to be realized by using a five-axis high-precision machining tool. The equipment is very expensive and free When processing curved surfaces, only slow cutters can be used, and the surface roughness processed is much worse than that processed by high-precision rotary lathes

Images