The aim of this work is to study in detail the drilling process on glass by CO2 laser. The study parameters considered in the present experiments are based on the laser beam power of range (30% - 80% of 25 W) and an e...The aim of this work is to study in detail the drilling process on glass by CO2 laser. The study parameters considered in the present experiments are based on the laser beam power of range (30% - 80% of 25 W) and an exposure time for drilling (2 - 8 s). The measured diameters of holes by optical methods are between [300 - 800 μm]. The results obtained by optical observations suggest that ordinary and mineral glasses cannot withstand to a contact of the laser beam and crack during the formation of the drilling hole. The minimum power and duration of exposure are the optimal parameters for drilling the organic glass, we observe no micro-cracks, and again we see that the edges of the holes have a good surface quality with a high aspect ratio.展开更多
Mid-high spatial frequency errors are often induced on optical surfaces polished by computer-controlled optical surfacing (CCOS) processes. In order to efficiently remove these errors, which would degrade the performa...Mid-high spatial frequency errors are often induced on optical surfaces polished by computer-controlled optical surfacing (CCOS) processes. In order to efficiently remove these errors, which would degrade the performances of optical systems, the ability of a CCOS process to correct the errors have been investigated based on the convolution integral model in view of the availability of material removal. To quantify the ability, some conceptions, such as figure correcting ability and material removal availability (MRA), have been proposed. The research result reveals that the MRA of the CCOS process to correct a single spatial frequency error is determined by its tool removal function (TRF), and it equals the normalized amplitude spectrum of the Fourier transform of its TRF. Finally, three sine surfaces were etched using ion beam figuring (IBF), which is a typical CCOS process. The experimental results have verified the theoretical analysis. The employed method and the conclusions of this work provide a useful mathematical basis to analyze and optimize CCOS processes.展开更多
为深入了解碳化硅陶瓷的光学表面加工性能,采用常压固相烧结法制备了碳化硅陶瓷,在保证致密度的前提下,通过改变碳的含量,研究了残余碳对SiC陶瓷抛光面的表面质量和光学性能的影响。研究发现,C的质量含量为3%～7%时,SiC陶瓷抛光表面的RM...为深入了解碳化硅陶瓷的光学表面加工性能,采用常压固相烧结法制备了碳化硅陶瓷,在保证致密度的前提下,通过改变碳的含量,研究了残余碳对SiC陶瓷抛光面的表面质量和光学性能的影响。研究发现,C的质量含量为3%～7%时,SiC陶瓷抛光表面的RMS(root mean square)粗糙度均约为2nm。当C含量为3%～6%时,SiC陶瓷抛光表面在400～750nm波段的全反射率、漫反射率和镜面反射率无明显变化;当C含量升至7%时,全反射率稍有降低,漫反射率稍有上升,镜面反射率稍有降低。其原因可能是过多的残余碳引起SiC陶瓷的折射率下降和产生光学散射,最终造成镜面反射率降低。展开更多
文摘The aim of this work is to study in detail the drilling process on glass by CO2 laser. The study parameters considered in the present experiments are based on the laser beam power of range (30% - 80% of 25 W) and an exposure time for drilling (2 - 8 s). The measured diameters of holes by optical methods are between [300 - 800 μm]. The results obtained by optical observations suggest that ordinary and mineral glasses cannot withstand to a contact of the laser beam and crack during the formation of the drilling hole. The minimum power and duration of exposure are the optimal parameters for drilling the organic glass, we observe no micro-cracks, and again we see that the edges of the holes have a good surface quality with a high aspect ratio.
基金Supported by the National Basic Research Program of China("973"Project)the National Natural Science Foundation of China(Grant No.50775215)
文摘Mid-high spatial frequency errors are often induced on optical surfaces polished by computer-controlled optical surfacing (CCOS) processes. In order to efficiently remove these errors, which would degrade the performances of optical systems, the ability of a CCOS process to correct the errors have been investigated based on the convolution integral model in view of the availability of material removal. To quantify the ability, some conceptions, such as figure correcting ability and material removal availability (MRA), have been proposed. The research result reveals that the MRA of the CCOS process to correct a single spatial frequency error is determined by its tool removal function (TRF), and it equals the normalized amplitude spectrum of the Fourier transform of its TRF. Finally, three sine surfaces were etched using ion beam figuring (IBF), which is a typical CCOS process. The experimental results have verified the theoretical analysis. The employed method and the conclusions of this work provide a useful mathematical basis to analyze and optimize CCOS processes.
文摘为深入了解碳化硅陶瓷的光学表面加工性能,采用常压固相烧结法制备了碳化硅陶瓷,在保证致密度的前提下,通过改变碳的含量,研究了残余碳对SiC陶瓷抛光面的表面质量和光学性能的影响。研究发现,C的质量含量为3%～7%时,SiC陶瓷抛光表面的RMS(root mean square)粗糙度均约为2nm。当C含量为3%～6%时,SiC陶瓷抛光表面在400～750nm波段的全反射率、漫反射率和镜面反射率无明显变化;当C含量升至7%时,全反射率稍有降低,漫反射率稍有上升,镜面反射率稍有降低。其原因可能是过多的残余碳引起SiC陶瓷的折射率下降和产生光学散射,最终造成镜面反射率降低。
