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摘要:
为了产生半径可自由调控的聚焦环形 且确保离焦后光束强度仍均匀,本文提出一种透射-反射式组合的环形光光学系统设计方法。对于透射式系统,基于等能量分割原理,建立入射光与出射光投射高度的映射函数,优化透镜的各项参数,将入射的高斯光先整形成平顶圆形光,实现光束强度均匀化。反射式系统通过调整焦面环形光直径调控范围、工作距离等参数,结合几何光线追迹原理,计算圆锥反射镜、抛物柱面镜及动镜的各项参数,将平顶圆形光再整形成环形光。实验结果表明:当动镜半顶角为16°时,所设计系统能够实现聚焦环形光半径在15~30 mm范围的自由调控,尺寸误差不超过0.05 mm,离焦后强度均匀度达到84%。该设计方法无需更换系统镜片即可兼顾强度均匀性和尺寸自由度,可操作性好,产生的环形光加工精度和效率更高。
Abstract:We present a method for designing a transmissive-reflective combined optical system to generate a focused ring-shaped laser beam. The design aims to achieve a freely adjustable radius for the focused ring-shaped laser beam and ensure uniform beam intensity even after defocusing. Based on the principle of equal energy splitting, the transmissive system establishes mapping functions for the input and output light projection height. It optimizes the lens parameters to shape the incident Gaussian light into a flat-topped circular shape, thus achieving uniformity of beam intensity. On the other hand, the reflective system uses the adjustable diameter range of the focal plane ring-shaped light and working distance parameters. By applying the principle of geometric ray tracing, it calculates the parameters of the conical reflecting mirror, parabolic cylindrical mirror, and dynamic mirror, then the flat-topped circular light is transformed into a ring-shaped light. The experimental results show that when the half-apex angle of the dynamic mirror is 16°, the designed system can achieve a freely adjustable radius for the focused ring-shaped laser beam from 15 mm to 30 mm with a size error not more than 0.05 mm, and the intensity uniformity after defocusing reaches 84%. The design method can achieve both uniformity of intensity and freedom of size adjustment without replacing the system lens. It has good operability and yields higher precision and efficiency in the processing of ring-shaped light.
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Key words:
- optical system /
- ring-shaped laser /
- radius control /
- defocus uniformity
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表 1 初始条件
Table 1. Initial condition
入瞳半径
d/mm波长
λ/nmD
/mmS
/mm工作距离
/mm均匀度
/%数值 12 632.8 30 15 150~170 >80% 表 2 透镜参数
Table 2. Lens parameters
有效直径/mm 材料 厚度/mm 曲率半径/mm Conic A4 A6 A8 A10 面型1 27 PMMA 15 5 −1.914 1.047×10−4 −3.943×10−7 1.167×10−9 −1.609×10−12 面型2 36 PMMA 12 17.877 −0.959 −1.983×10−4 3.056×10−8 −4.444×10−11 7.283×10−14 表 3 反射镜及面上特征点参数
Table 3. Parameters of characteristic points on the mirror and surface
α(°) Q F f/mm K θ(°) L/mm ΔZ/mm 材料 数值 45 (18,−114.04) (−50,−22.04) 160 (70,−180.04) 16 27.2 4.5 7075-T6 -
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