Non-sequential Ray-tracing Software Research Articles

Design method of diffuse transmission free-form surface combined with collimation lens array

Lighting-emitting diodes are widely applied in lighting systems, and diffusers are commonly used in systems for indirect illumination. In this paper, a design method of diffuse transmission free-form surface combined with collimation lens array is proposed. Based on the Lambertian characteristics of lighting-emitting diodes and the principle of collimation lenses, a mathematical model of diffuser with ideal diffuse transmission free-form surface is established. We propose a method of the preset collimation surface to connect the free-form surface and the collimation lens array, and derive the nonlinear algebraic equation of the diffuse transmission free-form surface according to the connection effect of the preset collimation surface. Then, solving the equation numerically by MATLAB, the profile of the diffuse transmission free-form surface is obtained. Finally, the non-sequential ray tracing software TracePro is used to simulate the irradiance distribution of the target plane. The results show better uniformity and higher efficiency comparing with the lighting system using diffuse transmission free-form surface alone and the traditional diffuse transmission lighting system.

In vitro and schematic model eye assessment of glare or positive dysphotopsia-type photic phenomena: Comparison of a new material IOL to other monofocal IOLs

To compare the glare-type photic phenomena for a new intraocular lens (IOL) to other monofocal IOLs, and to investigate how IOL design features might affect these phenomena. Alcon Laboratories, Inc., Fort Worth, Texas; John A Moran Eye Center, University of Utah, Salt Lake City, USA. Schematic model eye evaluation and invitro study. Five monofocal IOL models (Clareon CNA0T0, Tecnis ZCB00, enVista MX60, Eternity W-60, and Vivinex XY1) were used to evaluate glare or positive dysphotopsia-type phenomena. Optical simulations of incoming light were generated using nonsequential ray-tracing software based on a collimated light source for various off-axis angles of illumination. The simulation analyses were verified using a laboratory invitro bench-top glare measurement system. The Clareon and Vivinex IOLs produced focused off-axis images with negligible peripheral glare characteristics. The Tecnis and enVista IOLs produced dispersed images with additional glare characteristics at 45 degrees of off-axis illumination and higher. The Eternity IOL showed the highest edge-reflected glare characteristic, likely because of its straight optic edge geometry. The laboratory bench images and glare intensity profiles were consistent with the simulation data. Invitro and nonsequential ray-tracing evaluations showed that straight optic edges and peripheral nonimaging optic geometry might contribute to positive dysphotopsia. The IOL designs with optic edge curvature and full functional optics demonstrated the lowest level of glare-type photic phenomena. Only clinical studies can confirm whether the differences observed between the IOLs invitro are clinically significant.

Augmented design and analysis of computer experiments: a novel tolerance embedded global optimization approach applied to SWIR hyperspectral illumination design.

A novel meta-heuristic approach for minimizing nonlinear constrained problems is proposed, which offers tolerance information during the search for the global optimum. The method is based on the concept of design and analysis of computer experiments combined with a novel two phase design augmentation (DACEDA), which models the entire merit space using a Gaussian process, with iteratively increased resolution around the optimum. The algorithm is introduced through a series of cases studies with increasing complexity for optimizing uniformity of a short-wave infrared (SWIR) hyperspectral imaging (HSI) illumination system (IS). The method is first demonstrated for a two-dimensional problem consisting of the positioning of analytical isotropic point sources. The method is further applied to two-dimensional (2D) and five-dimensional (5D) SWIR HSI IS versions using close- and far-field measured source models applied within the non-sequential ray-tracing software FRED, including inherent stochastic noise. The proposed method is compared to other heuristic approaches such as simplex and simulated annealing (SA). It is shown that DACEDA converges towards a minimum with 1 % improvement compared to simplex and SA, and more importantly requiring only half the number of simulations. Finally, a concurrent tolerance analysis is done within DACEDA for to the five-dimensional case such that further simulations are not required.

SU-D-213-03: Towards An Optimized 3D Scintillation Dosimetry Tool for Quality Assurance of Dynamic Radiotherapy Techniques

Purpose: The purpose of this work is to simulate a multi-focus plenoptic camera used as the measuring device in a real-time three-dimensional scintillation dosimeter. Simulating and optimizing this realistic optical system will bridge the technological gap between concept validation and a clinically viable tool that can provide highly efficient, accurate and precise measurements for dynamic radiotherapy techniques. Methods: The experimental prototype, previously developed for proof of concept purposes, uses an off-the-shelf multi-focus plenoptic camera. With an array of interleaved microlenses of different focal lengths, this camera records spatial and angular information of light emitted by a plastic scintillator volume. The three distinct microlens focal lengths were determined experimentally for use as baseline parameters by measuring image-to-object magnification for different distances in object space. A simulated plenoptic system was implemented using the non-sequential ray tracing software Zemax: this tool allows complete simulation of multiple optical paths by modeling interactions at interfaces such as scatter, diffraction, reflection and refraction. The active sensor was modeled based on the camera manufacturer specifications by a 2048×2048, 5 µm-pixel pitch sensor. Planar light sources, simulating the plastic scintillator volume, were employed for ray tracing simulations. Results: The microlens focal lengths were determined to be 384, 327more » and 290 µm. A realistic multi-focus plenoptic system, with independently defined and optimizable specifications, was fully simulated. A f/2.9 and 54 mm-focal length Double Gauss objective was modeled as the system’s main lens. A three-focal length hexagonal microlens array of 250-µm thickness was designed, acting as an image-relay system between the main lens and sensor. Conclusion: Simulation of a fully modeled multi-focus plenoptic camera enables the decoupled optimization of the main lens and microlens specifications. This work leads the way to improving the 3D dosimeter’s achievable resolution, efficiency and build for providing a quality assurance tool fully meeting clinical needs. M.R. is financially supported by a Master’s Canada Graduate Scholarship from the NSERC. This research is also supported by the NSERC Industrial Research Chair in Optical Design.« less

Simple Methods to Approximate CPC Shape to Preserve Collection Efficiency

The compound parabolic concentrator (CPC) is the most efficient reflective geometry to collect light to an exit port. Anyway, to allow its actual use in solar plants or photovoltaic concentration systems, a tradeoff between system efficiency and cost reduction, the two key issues for sunlight exploitation, must be found. In this work, we analyze various methods to model an approximated CPC aimed to be simpler and more cost-effective than the ideal one, as well as to preserve the system efficiency. The manufacturing easiness arises from the use of truncated conic surfaces only, which can be realized by cheap machining techniques. We compare different configurations on the basis of their collection efficiency, evaluated by means of nonsequential ray-tracing software. Moreover, due to the fact that some configurations are beam dependent and for a closer approximation of a real case, the input beam is simulated as nonsymmetric, with a nonconstant irradiance on the CPC internal surface.

Projection display for the generation of two orthogonal polarized images using liquid crystal on silicon panels and light emitting diodes

We present a projection system that is capable of two-dimensional and three-dimensional image display. A novel projection architecture is discussed that can simultaneously generate two linear polarized full-color images with orthogonal states of polarization using only one optical system. Both images are modulated by using two high-resolution liquid crystal on silicon panels that are illuminated with high-power light emitting diodes. The optical core and the illumination system are simulated, characterized, and optimized with nonsequential ray tracing software. A proof-of-concept demonstrator of the entire projection system is built and characterized. Important component specifications are discussed to improve the system performance.