A free-form lens (FFL) is a special surface that is difficult to be fabricated. FFL are usually fabricated by computer-controlled optical surfacing (CCOS) technique. During CCOS, the material removal amount is determi...A free-form lens (FFL) is a special surface that is difficult to be fabricated. FFL are usually fabricated by computer-controlled optical surfacing (CCOS) technique. During CCOS, the material removal amount is determined by the unit removal function (URF) convoluting with the input data――the dwell time. When the removal amount and the URF are known, how to solve the input data involves the special algorithm――deconvolution. Usually, the input data are solved by virtue of low pass filter or iterative methods. However, an approximation solution would destroy the machining stability nec-essary to perform precisely CCOS. In this paper, to solve the input data, a new method that is based on the finite Fourier coefficient is put forward. It can give a continuous and accurate solution for fabricating choice. Several parameters are simulated, which influ-ence the process of CCOS, and evaluating on the effect of the method is also carried out. Experimental results verify that this method is suitable for guiding the manufacturing of high precision FFL.展开更多
The fabrication deviation of prisms and the error crosstalk are two major factors that produce serious systematic errors in dual-beam roll measurement based on a rhombic prism, and an error compensation method is put ...The fabrication deviation of prisms and the error crosstalk are two major factors that produce serious systematic errors in dual-beam roll measurement based on a rhombic prism, and an error compensation method is put forward in this letter to reduce these systematic errors. The rotation matrix, reflection matrix, and refraction matrix are used to calculate and obtain the mathematical relationship model of the roll angle as well as the fabrication deviation of prism and error crosstalk. The fabrication deviation can be obtained through comparison experiments and using the least square method. In this way, the systematic error of the roll measurement caused by fabrication deviation of prism and error crosstalk can be eliminated theoretically. The experimental results show that the maximum error of the roll angle measurement reduces evidently to 3.5″ from the previous 347.2″ after compensation.展开更多
基金This work was supported by the National Natural Science Foundation of China (Grant Nos. 50175062, 60508001).
文摘A free-form lens (FFL) is a special surface that is difficult to be fabricated. FFL are usually fabricated by computer-controlled optical surfacing (CCOS) technique. During CCOS, the material removal amount is determined by the unit removal function (URF) convoluting with the input data――the dwell time. When the removal amount and the URF are known, how to solve the input data involves the special algorithm――deconvolution. Usually, the input data are solved by virtue of low pass filter or iterative methods. However, an approximation solution would destroy the machining stability nec-essary to perform precisely CCOS. In this paper, to solve the input data, a new method that is based on the finite Fourier coefficient is put forward. It can give a continuous and accurate solution for fabricating choice. Several parameters are simulated, which influ-ence the process of CCOS, and evaluating on the effect of the method is also carried out. Experimental results verify that this method is suitable for guiding the manufacturing of high precision FFL.
基金supported by the National Natural Science Foundation of China under Grant Nos.51027006 and 50675017
文摘The fabrication deviation of prisms and the error crosstalk are two major factors that produce serious systematic errors in dual-beam roll measurement based on a rhombic prism, and an error compensation method is put forward in this letter to reduce these systematic errors. The rotation matrix, reflection matrix, and refraction matrix are used to calculate and obtain the mathematical relationship model of the roll angle as well as the fabrication deviation of prism and error crosstalk. The fabrication deviation can be obtained through comparison experiments and using the least square method. In this way, the systematic error of the roll measurement caused by fabrication deviation of prism and error crosstalk can be eliminated theoretically. The experimental results show that the maximum error of the roll angle measurement reduces evidently to 3.5″ from the previous 347.2″ after compensation.
