This paper presents a solution for design aspheric multifocal contact lens with various add powers. The multi-aspheric curve on the optical surface profile is replaced by a single freeform spline curve. A cubic spline curve is optimized to remove all unsmooth transitions between different vision correction zones and still satisfy the power distribution of the aspheric multifocal contact lens. The result shows that the contact lens using a cubic spline curve could provide not only a smooth lens surface profile but also a smooth power distribution that is difficultly obtained by an aspheric multifocal contact lens. The proposed contact lens is easily transferred to CAD format for further analysis or manufacture. Results of this study can be further applied for progressive contact lens design.
This paper investigates the mold design and related effects on an aspheric projector lens for Head Up Display
(HUD) with injection molding process. Injection flow analysis with a commercial software, Moldex3D has been
used to simulate this projector lens for filling, packing, shrinkage, and flow-induced residual stress. This
projector lens contains of variant thickness due to different aspheric design on both surfaces. Defects may be
induced as the melt front from the gate into the cavity with jet-flow phenomenon, short shot, weld line, and even
shrinkage. Thus, this paper performs a gate design to find the significant parameters including injection velocity,
melt temperature, and mold temperature. After simulation by the Moldex3D, gate design for the final assembly
of Head Up Display (HUD) has been obtained and then experimental tests have been proceeded for verification
of short-shot, weight variation, and flow-induced stress. Moreover, warpage analysis of the Head Up Display
(HUD) can be integrated with the optical design specification in future work.
With minimization of optical-electronics devices, conventional optical zoom lens component has been explored with
liquid lens and soft polymer membranes. This paper introduces a novel zoom lens system with a soft polymer material,
Polydimethylsiloxane (PDMS), its shape and curvature can be controlled by pneumatic pressure. Therefore, effective
focal length (EFL) of soft zoom lens (SZL) system can be controlled and altered. According to desired opto-mechanical
design, this ZL has been accessed to determine the optical specifications. After the pressure activated from 0 to 0.02MPa,
the change of EFL of the SZL system can reach up to 18.77% (33.44mm to 39.717mm). Experimental results show that
zoom effects of the developed SZL system are significantly affected by the shape, thickness and curing parameter of
PDMS soft lens. The SZL system has been verified with the function of zoom ability. Further research works on the
integration of the SZL system with imaging system for mobile devices or robot vision applications.
This paper is to design and fabricate an optical homogenizer with hybrid design of collimator, toroidal lens array, and
projection lens for beam shaping of Gaussian beam into uniform cylindrical beam. TracePro software was used to
design the geometry of homogenizer and simulation of injection molding was preceded by Moldflow MPI to evaluate the
mold design for injection molding process. The optical homogenizer is a cylindrical part with thickness 8.03 mm and
diameter 5 mm. The micro structure of toroidal array has groove height designed from 12 μm to 99 μm. An electrical
injection molding machine and PMMA (n= 1.4747) were selected to perform the experiment. Experimental results
show that the optics homogenizer has achieved the transfer ratio of grooves (TRG) as 88.98% and also the optical
uniformity as 68% with optical efficiency as 91.88%. Future study focuses on development of an optical homogenizer
for LED light source.
Stylus tip reconstruction is imperative in tracing and calibration of micro and nano surface roughness measurement either for surface roughness analyzer or for scanning probe microscopy. This research is to investigate the size effects on stylus tip reconstruction in micro and nano roughness measurement. Aspect ratios within and between tips and gages, such as Tip Aspect Ratio (TAR) of tip width to height, Gage Aspect Ratio (GAR), Height Aspect Ratio (HAR) of tip height to gage height, and Width Aspect Ratio (WAR) have been formulated to develop a stylus tip reconstruction method (STRM) to estimate tip profile from the measured profile image and the traced gage profile. A simulated program has been used to test the developed STRM with different aspect ratios of tips and gages. Experiments have been conducted on a Hommelwerke T4000 surface roughness analyzer with a TKL T100 tip of radius 5 μm and a Veeco Dektak 200 surface roughness analyzer with nominal radius values of stylus tip radius 12.5 μm to measure a traced roughness gage (Mitutoyo Serial No. 0300042) of step height of 10 μm and razor blade in ISO 5436 standard. Experimental results show that the difference of STRM on step gage and razor blade measurement is about 4 % and the developed STRM can be further used to estimate the geometric size effects of tip reconstruction in scanning probe microscopy (SPM).