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
Collimating lenses are an important component of laser ranging systems,and high overload environments severely affect the beam shaping effect of such lenses.This study proposes a buffer isolation method on the basis o...Collimating lenses are an important component of laser ranging systems,and high overload environments severely affect the beam shaping effect of such lenses.This study proposes a buffer isolation method on the basis of impact stress wave attenuation theory for collimating lens spacers,ANSYS finite element software was applied to simulate the high load dynamics of collimating lenses,and the buffer isolation performance of different materials and composite structures was compared and analysed.Optical simulation analysis of the collimating lenses under different buffer conditions was performed using ZEMAX software to study the mechanism by which a high overload affects the collimating lenses.High overload and optical shaping experiments based on theoretical analysis were further conducted.Results showed the superiority of butadiene rubber to polytetrafluoroethylene after application of 70000 g impact acceleration.The combination-gasket method was superior to the single-gasket method,and the sandwich combination-gasket method was superior to the double-layer combination-gasket method.展开更多
A two-dimensional numerical model was used to explain the liquefaction mechanism of double sand lenses and the corresponding soil deformation due to the cyclic loading. Moreover, in order to investigate the influences...A two-dimensional numerical model was used to explain the liquefaction mechanism of double sand lenses and the corresponding soil deformation due to the cyclic loading. Moreover, in order to investigate the influences of the soil characteristics and input loading data a parametric study was carried out on the essential parameters affecting the soil settlement, and so the variation of these parameters with the corresponding displacements was mainly examined. At last, the results obtained from the numerical analyses of double sand lenses and a continuous sand layer with similar characteristics were compared with those of an estimating method proposed by ISHIHARA and YOSHIMINE. The comparisons show that the settlements due to liquefaction of the continuous sand layer in both numerical and the estimating method are in a good agreement with and are obviously greater than those of double sand lenses.展开更多
With the rapid development of information and multi me dia technologies, the demand for the optical plastic aspheric elements used in o pto-electronic devices, camera, optical disc and projector lens etc. has been i n...With the rapid development of information and multi me dia technologies, the demand for the optical plastic aspheric elements used in o pto-electronic devices, camera, optical disc and projector lens etc. has been i ncreased rapidly in the recent years. The key technologies of fabrication of asp heric plastic lens are the design and manufacturing moulds, selection of proper injection moulding equipment, and optimization of injection moulding parameters etc. In this paper, the effect of injection pressure, moulding temperature, cool ing time and injection speed on the surface profile of the lenses during injecti on and holding process is investigated. Surface quality of plastic lenses is mea sured by Talysurf Texture Measuring System. The experimental results showed that the injection pressure and moulding temperature are important parameters compar ing to cooling time and injection speed. A bit change of injection pressure or m oulding temperature will affect the property of the surface profile. Either incr easing injection pressure or mould temperature can achieve less shrinkage. Other wise, a lower injection pressure will produce more shrinkage, more air traps and a lower mould temperature results greater warp and higher shrinkage. The dynami c process of injection for optical plastic lenses is simulated by 3D Moldflow pl astic Insight software (MPI). The MPI will help us to optimize injection mouldin g parameters.展开更多
At present, the main work of electron optical system CAD is solving equations and calculating mumerical values. However, the design perhaps needs more inference and expertise than numerical calculations because the st...At present, the main work of electron optical system CAD is solving equations and calculating mumerical values. However, the design perhaps needs more inference and expertise than numerical calculations because the structure of electron lens system is complicated. In this paper, a primary expert system is applied to design the electron lens system intelligently. This expert system is combined with SEU-3D program which is used to simulate the electron optical system to optimize the electron lens systems. In spite of this, the expert system which is established in this paper can also be used to diagnose the electron lens system. Although the knowledge base is small and rules are not abundant, this paper has used this system to obtain some very useful results. The initial success with this system suggests that further work need to be done whether more rules and knowledge will be added to extend the ability of expert system.展开更多
Objective To compare the efficacy of toric implantable collamer lens(Toric-ICL)and femtosecond laser-assisted in situ keratomileusis(FS-LASIK)for myopia correction in patients with moderate to high myopia complicated ...Objective To compare the efficacy of toric implantable collamer lens(Toric-ICL)and femtosecond laser-assisted in situ keratomileusis(FS-LASIK)for myopia correction in patients with moderate to high myopia complicated with astigmatism.Methods We retrospectively collected data from 64 patients(aged 18-42 years)with moderate to high myopia complicated with astigmatism(128 eyes)undergoing either Toric-ICL(28 patients/56 eyes)or FS-LASIK(36 patients/72 eyes)at our department between January,2019 and December,2020.The changes of uncorrected distance visual acuity(UCVA),spherical equivalent(SE),mean astigmatism correction index(CI),corneal endothelial cell density(ECD)and intraocular pressure(IOP)following the procedures were compared between the two groups.Results In FS-LASIK group,all the eyes(72/72)achieved an UCVA≥1.0,similar to the rate in Toric-ICL group(55/56 eyes;P=0.2374).The postoperative SE was also comparable between FS-LASIK and Toric-ICL groups[0.43±0.06 D(range:-1.0 to 1.50 D)vs 0.38±0.05 D(range:-0.75 to 1.00 D);P=0.56].The mean astigmatism CI was significantly higher in FS-LASIK group than in Toric-ICL group(0.8561 vs 0.7176;P<0.0001),and 88.89%of the eyes in FS-LASIK group and 69.64%in Toric-ICL group had postoperative astigmatism≤0.50 D.No significant changes were observed in postoperative corneal ECD in FS-LASIK group,whereas ECD decreased significantly after the procedure in Toric-ICL group(P=0.0057).The patients undergoing Toric-ICL exhibited no significant changes of postoperative IOP,but the patients receiving FS-LASIK had significantly reduced IOP after the procedure(P<0.001).Conclusion Although the patients included in Toric-ICL group had higher myopia and astigmatism,Toric-ICL still showed better predictability and efficacy for astigmatic correction in Toric-ICL group.Toric-ICL is an effective and safe equivalent of FS-LASIK for correcting moderate myopia but can be more advantageous for correcting high myopia with astigmatism.展开更多
目的观察偏心和倾斜对不同焦点设计人工晶状体(IOL)光学质量的影响。方法采用紫外分光光度计UV 3300 PC测量+20 D的蔡司MICS平台单焦点IOL CT ASPHINA 509M(509M)、双焦点IOL AT LISA 809M(809M)和三焦点IOL AT LISA Tri 839MP(839MP)...目的观察偏心和倾斜对不同焦点设计人工晶状体(IOL)光学质量的影响。方法采用紫外分光光度计UV 3300 PC测量+20 D的蔡司MICS平台单焦点IOL CT ASPHINA 509M(509M)、双焦点IOL AT LISA 809M(809M)和三焦点IOL AT LISA Tri 839MP(839MP)的光谱透过率。采用体外光学质量测试系统OptiSpheric IOL R&D分别在3.0 mm和4.5 mm孔径下,测量IOL在居中、偏心(0.3、0.5、0.7、0.9和1.1 mm)和倾斜(3°、5°、7°、9°和11°)状态下,不同焦点处的50 lp/mm空间频率下调制传递函数(MTF)值、MTF曲线和美国空军(USAF)分辨率测试图。结果3种IOL均滤过400 nm波长以下的紫外线光谱。居中位置时,在3.0 mm孔径下单焦点IOL 509M远焦点处的MTF值为0.772,双焦点IOL 809M远、近焦点处的MTF值分别为0.467和0.282,三焦点IOL 839MP远、中、近焦点处的MTF值分别为0.416、0.147和0.229;在4.5 mm孔径下,单焦点IOL 509M远焦点处的MTF值为0.664,双焦点IOL 809M远、近焦点处的MTF值分别为0.506和0.264,三焦点IOL 839MP远、中、近焦点处的MTF值分别为0.392、0.107和0.210。3种IOL相比,远焦点处509M的MTF值最高,809M次之,839MP最差;近焦点处IOL 809M的MTF值高于IOL 839MP。偏心和倾斜时,远、近焦点处各IOL的MTF值差异与居中时一致。相同偏心和倾斜程度时,在3.0 mm孔径下各IOL的光学质量较4.5 mm孔径下更佳。随着偏心和倾斜程度增加,各IOL光学质量整体呈下降趋势。3种IOL在偏心0.3 mm、倾斜5°时均出现光学质量下降。结论蔡司MICS平台设计的IOL光谱透过率一致,具有紫外线滤过功能。3种IOL相比,居中位置时,远、中、近焦点处分别以509M、839MP和809M光学质量最佳;发生偏心和倾斜时,远、近焦点处分别以509M和809M抗偏心和倾斜能力最好。相同偏心或倾斜程度时,小孔径下各IOL光学质量较大孔径更佳。偏心0.3 mm、倾斜5°以上时,IOL各焦点处光学质量均较居中时下降明显。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National Natural Science Foundation of China(51605227)the Fundamental Research Funds for the Central Universities(NUST30915011303)。
文摘Collimating lenses are an important component of laser ranging systems,and high overload environments severely affect the beam shaping effect of such lenses.This study proposes a buffer isolation method on the basis of impact stress wave attenuation theory for collimating lens spacers,ANSYS finite element software was applied to simulate the high load dynamics of collimating lenses,and the buffer isolation performance of different materials and composite structures was compared and analysed.Optical simulation analysis of the collimating lenses under different buffer conditions was performed using ZEMAX software to study the mechanism by which a high overload affects the collimating lenses.High overload and optical shaping experiments based on theoretical analysis were further conducted.Results showed the superiority of butadiene rubber to polytetrafluoroethylene after application of 70000 g impact acceleration.The combination-gasket method was superior to the single-gasket method,and the sandwich combination-gasket method was superior to the double-layer combination-gasket method.
文摘A two-dimensional numerical model was used to explain the liquefaction mechanism of double sand lenses and the corresponding soil deformation due to the cyclic loading. Moreover, in order to investigate the influences of the soil characteristics and input loading data a parametric study was carried out on the essential parameters affecting the soil settlement, and so the variation of these parameters with the corresponding displacements was mainly examined. At last, the results obtained from the numerical analyses of double sand lenses and a continuous sand layer with similar characteristics were compared with those of an estimating method proposed by ISHIHARA and YOSHIMINE. The comparisons show that the settlements due to liquefaction of the continuous sand layer in both numerical and the estimating method are in a good agreement with and are obviously greater than those of double sand lenses.
文摘With the rapid development of information and multi me dia technologies, the demand for the optical plastic aspheric elements used in o pto-electronic devices, camera, optical disc and projector lens etc. has been i ncreased rapidly in the recent years. The key technologies of fabrication of asp heric plastic lens are the design and manufacturing moulds, selection of proper injection moulding equipment, and optimization of injection moulding parameters etc. In this paper, the effect of injection pressure, moulding temperature, cool ing time and injection speed on the surface profile of the lenses during injecti on and holding process is investigated. Surface quality of plastic lenses is mea sured by Talysurf Texture Measuring System. The experimental results showed that the injection pressure and moulding temperature are important parameters compar ing to cooling time and injection speed. A bit change of injection pressure or m oulding temperature will affect the property of the surface profile. Either incr easing injection pressure or mould temperature can achieve less shrinkage. Other wise, a lower injection pressure will produce more shrinkage, more air traps and a lower mould temperature results greater warp and higher shrinkage. The dynami c process of injection for optical plastic lenses is simulated by 3D Moldflow pl astic Insight software (MPI). The MPI will help us to optimize injection mouldin g parameters.
文摘At present, the main work of electron optical system CAD is solving equations and calculating mumerical values. However, the design perhaps needs more inference and expertise than numerical calculations because the structure of electron lens system is complicated. In this paper, a primary expert system is applied to design the electron lens system intelligently. This expert system is combined with SEU-3D program which is used to simulate the electron optical system to optimize the electron lens systems. In spite of this, the expert system which is established in this paper can also be used to diagnose the electron lens system. Although the knowledge base is small and rules are not abundant, this paper has used this system to obtain some very useful results. The initial success with this system suggests that further work need to be done whether more rules and knowledge will be added to extend the ability of expert system.
文摘Objective To compare the efficacy of toric implantable collamer lens(Toric-ICL)and femtosecond laser-assisted in situ keratomileusis(FS-LASIK)for myopia correction in patients with moderate to high myopia complicated with astigmatism.Methods We retrospectively collected data from 64 patients(aged 18-42 years)with moderate to high myopia complicated with astigmatism(128 eyes)undergoing either Toric-ICL(28 patients/56 eyes)or FS-LASIK(36 patients/72 eyes)at our department between January,2019 and December,2020.The changes of uncorrected distance visual acuity(UCVA),spherical equivalent(SE),mean astigmatism correction index(CI),corneal endothelial cell density(ECD)and intraocular pressure(IOP)following the procedures were compared between the two groups.Results In FS-LASIK group,all the eyes(72/72)achieved an UCVA≥1.0,similar to the rate in Toric-ICL group(55/56 eyes;P=0.2374).The postoperative SE was also comparable between FS-LASIK and Toric-ICL groups[0.43±0.06 D(range:-1.0 to 1.50 D)vs 0.38±0.05 D(range:-0.75 to 1.00 D);P=0.56].The mean astigmatism CI was significantly higher in FS-LASIK group than in Toric-ICL group(0.8561 vs 0.7176;P<0.0001),and 88.89%of the eyes in FS-LASIK group and 69.64%in Toric-ICL group had postoperative astigmatism≤0.50 D.No significant changes were observed in postoperative corneal ECD in FS-LASIK group,whereas ECD decreased significantly after the procedure in Toric-ICL group(P=0.0057).The patients undergoing Toric-ICL exhibited no significant changes of postoperative IOP,but the patients receiving FS-LASIK had significantly reduced IOP after the procedure(P<0.001).Conclusion Although the patients included in Toric-ICL group had higher myopia and astigmatism,Toric-ICL still showed better predictability and efficacy for astigmatic correction in Toric-ICL group.Toric-ICL is an effective and safe equivalent of FS-LASIK for correcting moderate myopia but can be more advantageous for correcting high myopia with astigmatism.
