A new design of total internal reflection(TIR)lens was presented which had a freeform Fresnel surface in the central part of the front to improve the heat dissipation capability.Snell’s law and the reflection law wer...A new design of total internal reflection(TIR)lens was presented which had a freeform Fresnel surface in the central part of the front to improve the heat dissipation capability.Snell’s law and the reflection law were applied to construct the freeform refractive surface and the freeform reflective surface for the TIR lens.The freeform refractive surface was transformed into the freeform Fresnel surface with universal design method of Fresnel lens.The simulation result for the freeform Fresnel TIR lens obtained by Monte Carlo ray tracing shows that the far field illumination uniformity of 82.0%and the luminous efficiency of 96.6%are achieved for the light source size of 2 mm×2 mm,in the meanwhile the lens weight is only 21.94 g.The freeform Fresnel TIR lens has nearly 20%reduction in lens weight and volume,only a 2%reduction in luminous efficiency,and no reduction in illumination uniformity compared to the TIR lens without the Fresnel surface.The result indicates that the Fresnelization for freeform surface of TIR lens can significantly reduce the volume and weight of TIR lens and shorten the optical path length,thus effectively improve its heat dissipation efficiency and service life while maintaining a high performance.展开更多
The inverse design of electron lens is realized by two different methods in this paper. One is damped least square method and the other is the artificial neural network method. Their merits and defects are discussed a...The inverse design of electron lens is realized by two different methods in this paper. One is damped least square method and the other is the artificial neural network method. Their merits and defects are discussed according to our calculation results in the paper. In the condition of selecting the learning samples properly, the artificial neural network has obvious advantages in the inverse design of electron lens. It is an effective method to solve the inverse design problem in the electron optic system.展开更多
文摘A new design of total internal reflection(TIR)lens was presented which had a freeform Fresnel surface in the central part of the front to improve the heat dissipation capability.Snell’s law and the reflection law were applied to construct the freeform refractive surface and the freeform reflective surface for the TIR lens.The freeform refractive surface was transformed into the freeform Fresnel surface with universal design method of Fresnel lens.The simulation result for the freeform Fresnel TIR lens obtained by Monte Carlo ray tracing shows that the far field illumination uniformity of 82.0%and the luminous efficiency of 96.6%are achieved for the light source size of 2 mm×2 mm,in the meanwhile the lens weight is only 21.94 g.The freeform Fresnel TIR lens has nearly 20%reduction in lens weight and volume,only a 2%reduction in luminous efficiency,and no reduction in illumination uniformity compared to the TIR lens without the Fresnel surface.The result indicates that the Fresnelization for freeform surface of TIR lens can significantly reduce the volume and weight of TIR lens and shorten the optical path length,thus effectively improve its heat dissipation efficiency and service life while maintaining a high performance.
基金the Scientific Research Foundation for Returned Overseas Chinese Scholars, State EducationCommission.
文摘The inverse design of electron lens is realized by two different methods in this paper. One is damped least square method and the other is the artificial neural network method. Their merits and defects are discussed according to our calculation results in the paper. In the condition of selecting the learning samples properly, the artificial neural network has obvious advantages in the inverse design of electron lens. It is an effective method to solve the inverse design problem in the electron optic system.
