Worldwide, ESSILOR International provides customers with Progressive Addition Lenses (PAL), which replace bifocal lenses. Thermal replication is one process to produce glass moulds for PAL, using sagged glass on a cer...Worldwide, ESSILOR International provides customers with Progressive Addition Lenses (PAL), which replace bifocal lenses. Thermal replication is one process to produce glass moulds for PAL, using sagged glass on a ceramic slumping block. In this paper, thermal replication for producing PAL glass moulds is developed through 3D modelling and experimentation. Our numerical approach is validated by comparing it with experimentation on the global 3D topology of the sagged glass. It is also validated by using more severe optical comparison criteria, developed by ESSILOR International to analyze the conformity of their products. Through modelling, the thermal replication is analyzed by studying the evolving contact between the sagged glass and the ceramic slumping block during the thermal cycle and the glass flow on the upper side of the sagged glass.展开更多
3D printing technologies have expanded beyond the research laboratories where they were used solely for prototyping and have become widely used in several industries.The production of custom 3D objects has significant...3D printing technologies have expanded beyond the research laboratories where they were used solely for prototyping and have become widely used in several industries.The production of custom 3D objects has significant potential in optical applications.However,this necessitates extremely specific material properties,such as transparency,homogeneity,birefringence,and surface finish.Currently,the majority of optical objects are manufactured using plastics.Moreover,the 3D printing processes using polymers to produce optical objects have significant advantages,such as limited wastage,short manufacturing time,and easy customization.However,despite extensive efforts,no technology has achieved the production of objects perfectly suited for optical applications.The objective of this review is to summarize recent advances in the field of 3D printing for optics,with an emphasis on specific developments for dedicated applications,and to explore new candidate processes.展开更多
Objectives:To investigate the short-and long-term effects of myopia control spectacle lenses with highly aspherical lenslets(HAL)and slightly aspherical lenslets(SAL)on visual function and visual quality using data ob...Objectives:To investigate the short-and long-term effects of myopia control spectacle lenses with highly aspherical lenslets(HAL)and slightly aspherical lenslets(SAL)on visual function and visual quality using data obtained from a randomized controlled clinical trial.Methods:This was a prospective,randomized,controlled,and double-blinded study;170 myopic children aged 8–13 years were randomly assigned to the HAL,SAL,or single-vision spectacle lenses(SVL)groups.Distance and near visual acuity(VA)at high(100%)and low(10%)contrast in photopic and scotopic conditions,near phoria,stereoacuity,and accommodative lag,microfluctuations(AMFs),amplitude(AA)were measured after wearing lenses for 10 min,6 months,and 12 months.Results:In total,161 subjects completed all follow-up in 12 months and were included in the analysis.After 10 min of wearing,the HAL and SAL groups had lower scotopic and low-contrast VA than the SVL group(decreased 0.03–0.08 logMAR and 0.01–0.04 logMAR in different VAs in the HAL and SAL groups,respectively,all P<0.05).The reduction in VA was recovered at 12 months as the HAL and SAL groups exhibited significant VA improvements,and the VA was not different among the three groups(all P>0.05).The HAL and SAL groups had significantly larger AMFs than the SVL group(HAL vs.SAL vs.SVL:0.21±0.08 D vs.0.16±0.05 D vs.0.15±0.06 D at baseline,0.19±0.07 D vs.0.17±0.05 D vs.0.13±0.07 D at 12 months,all P<0.05).There were no significant differences in accommodative lag,AA,or phoria between the groups(all P>0.05).The HAL and SAL groups had reduced stereoacuity compared to the SVL group at baseline(70’vs.60’vs.50’,P=0.005),but no difference was observed at 12 months(70’vs.70’vs.70’,P=0.11).Conclusions:HAL and SAL have no significant influence on accommodation and phoria except had larger AMF than SVL.Scotopic VA and low-contrast VA are reduced with short-term HAL and SAL use but recovered to be at same level with the SVL after 1 year of use.展开更多
文摘Worldwide, ESSILOR International provides customers with Progressive Addition Lenses (PAL), which replace bifocal lenses. Thermal replication is one process to produce glass moulds for PAL, using sagged glass on a ceramic slumping block. In this paper, thermal replication for producing PAL glass moulds is developed through 3D modelling and experimentation. Our numerical approach is validated by comparing it with experimentation on the global 3D topology of the sagged glass. It is also validated by using more severe optical comparison criteria, developed by ESSILOR International to analyze the conformity of their products. Through modelling, the thermal replication is analyzed by studying the evolving contact between the sagged glass and the ceramic slumping block during the thermal cycle and the glass flow on the upper side of the sagged glass.
文摘3D printing technologies have expanded beyond the research laboratories where they were used solely for prototyping and have become widely used in several industries.The production of custom 3D objects has significant potential in optical applications.However,this necessitates extremely specific material properties,such as transparency,homogeneity,birefringence,and surface finish.Currently,the majority of optical objects are manufactured using plastics.Moreover,the 3D printing processes using polymers to produce optical objects have significant advantages,such as limited wastage,short manufacturing time,and easy customization.However,despite extensive efforts,no technology has achieved the production of objects perfectly suited for optical applications.The objective of this review is to summarize recent advances in the field of 3D printing for optics,with an emphasis on specific developments for dedicated applications,and to explore new candidate processes.
基金supported by the International S&T Cooperation Program of China(Grant No.2014DFA30940)Collaborative research project with Essilor International(Wenzhou Medical University Grant Nos.95013006,95016010 and 95020005).
文摘Objectives:To investigate the short-and long-term effects of myopia control spectacle lenses with highly aspherical lenslets(HAL)and slightly aspherical lenslets(SAL)on visual function and visual quality using data obtained from a randomized controlled clinical trial.Methods:This was a prospective,randomized,controlled,and double-blinded study;170 myopic children aged 8–13 years were randomly assigned to the HAL,SAL,or single-vision spectacle lenses(SVL)groups.Distance and near visual acuity(VA)at high(100%)and low(10%)contrast in photopic and scotopic conditions,near phoria,stereoacuity,and accommodative lag,microfluctuations(AMFs),amplitude(AA)were measured after wearing lenses for 10 min,6 months,and 12 months.Results:In total,161 subjects completed all follow-up in 12 months and were included in the analysis.After 10 min of wearing,the HAL and SAL groups had lower scotopic and low-contrast VA than the SVL group(decreased 0.03–0.08 logMAR and 0.01–0.04 logMAR in different VAs in the HAL and SAL groups,respectively,all P<0.05).The reduction in VA was recovered at 12 months as the HAL and SAL groups exhibited significant VA improvements,and the VA was not different among the three groups(all P>0.05).The HAL and SAL groups had significantly larger AMFs than the SVL group(HAL vs.SAL vs.SVL:0.21±0.08 D vs.0.16±0.05 D vs.0.15±0.06 D at baseline,0.19±0.07 D vs.0.17±0.05 D vs.0.13±0.07 D at 12 months,all P<0.05).There were no significant differences in accommodative lag,AA,or phoria between the groups(all P>0.05).The HAL and SAL groups had reduced stereoacuity compared to the SVL group at baseline(70’vs.60’vs.50’,P=0.005),but no difference was observed at 12 months(70’vs.70’vs.70’,P=0.11).Conclusions:HAL and SAL have no significant influence on accommodation and phoria except had larger AMF than SVL.Scotopic VA and low-contrast VA are reduced with short-term HAL and SAL use but recovered to be at same level with the SVL after 1 year of use.
