Total Internal Reflection Lens Research Articles

Optical Design of Portable LED Nails Lamps

<p>For the problem of low light efficiency caused by divergent and uneven energy distribution of commercial port-able LED nail lamps, we propose an optical system composed of a Lambertian LED, a total internal reflection lens and a microlens array. According to the simulation results, the optical system can project a 130mm×70mm rectangular light pattern with a uniformity of 85.17% on a screen 70mm away. In addition, the optical utilized factor of the rectangular light pattern is 87.85%, and the optical efficiency of the entire optical system is 83.93%.</p> <p> </p>

Total Internal Reflection Lens for Optical Wireless Receivers

This work considers the use of a freeform total internal reflection (TIR) lens for optical concentration and provides for the first time experimental results in the context of optical wireless communications (OWC). The lens is placed on a surface-mounted device (SMD) avalanche photodiode (APD) to minimize position tolerances and simplify assembly. The lens achieves a concentration ratio of go = 44.7 (16.5 dB) within the FOV center and exhibits an acceptance angle of ±5°. The TIR lens approach is validated by comparing eye diagrams and bit error ratios (BER) of a receiver with and without a TIR lens. For the measurements, non-return-to-zero (NRZ) on-off keying (OOK) signals are transmitted with a data rate of 1.289 Gbit/s.

Nonimaging metaoptics.

So far, metalenses have only been studied in imaging optics, where a point from the object space is mapped to a corresponding point in the image space. Here we explore metalenses and metamirrors for dealing with the optimal transfer of light energy. Owing to its compactness and high design flexibility, metasurface-based flat optics may open new opportunities in the nonimaging field, which deals with light concentration and illumination. The building blocks of metalenses are subwavelength-spaced scatterers. By suitably adjusting their shape, size, position, and orientation, one can control the light spatial distribution, as is desired in nonimaging problems. In this Letter, we introduce nonimaging metaoptics, review its basics, and briefly explore three cases: the compound-metasurface concentrator [analogous to the compound parabolic concentrator (CPC)], the total internal reflection (TIR) metalens (analogous to the TIR lens), and a simple condensing metalens.

Optical Design of an LED Lighting Source for Fluorescence Microscopes

In this study, we reveal an LED light source model applied in fluorescence microscopes. This optical model is composed of a confocal total internal reflection lens array system (CTLAS) with a nine-LED array. The CTLAS optical system that we designed consists of a total internal reflection (TIR) lens array and a confocal system. The electrical power of the nine-LED array is 7.9 watts, which is lower than traditional light sources, such as the original 120-watt halogen lamps used in fluorescence microscopes (Zeiss, Axio Imager 2). We have successfully applied the CTLAS system to an Axio Imager 2 fluorescence microscope to observe the vascular bundle organization, modified with Cy3 fluorescence molecules, and have found that in the process of system assembly, the fabrication errors of optical lenses could have a critical effect on the CTLAS system. The results of our experiment show that, in order to achieve the same illuminance as that of the halogen lamp, the displacement error tolerances of the lateral x-axis and the longitudinal z-axis must be controlled within 1.3 mm and 1.7 mm, respectively.

Using design of experiment for parameter optimization on smart headlamp optics design.

This research focuses on the design of the optical microstructure, and the design of four kinds of light distribution for vehicles' passing beam and driving beam optical structures under the regulation ECE R123. The results show that the passing beam achieves the target light distribution with multiple light patterns superimposed by reflectors, and can meet the four segment light types under the regulations: Class C, Class V, Class E, and Class W. With the structural design method of the reflector, a cutoff line is formed under the structure without a visor to reduce the energy waste caused by the shielding structure, so that the maximum luminosity of the passing beam under the road section can reach 75,980.7cd and the simulated maximum photometric value can reach 69,705.9cd under Class W. The driving beam uses the total internal reflection (TIR) lens design to find the optimal 36° angle of the lens to effectively achieve the straightening and brightness enhancement of the light, and then uses the response surface methodology to optimize the optical divergence of the parameters of the microlenticular lens structure on the TIR lens to adjust the width and flatness of the light type. Among them, the radius of curvature, the thickness of the lens, and the length of the single lens are selected as the factors. Using the experimental design method of the reaction surface, the optimal solution of the driving beam design is found. The optimal solution is combined into a radius of curvature of 14.99mm in the X direction and 25.22mm in the Y direction, the overall thickness is 1.5mm, and the length of a single curved surface is 2.43. Each factor is within the limit, and the maximum brightness in the center is 213,866cd.

Design of an energy-efficient marine signal light based on white LEDs

In this paper, we proposed and demonstrated a new design of marine signal light based on a phosphor-converted white light emitting diode. The light pattern was shaped in the vertical and horizontal directions, respectively, by a collimating total internal reflection lens with cylindrical lens array and a slanted shoulder to fit the requirement in the regulation. The vertical intensity distribution was collimated to 9° through an appropriate volume of the total internal reflection lens to fit the etendue of the light source. The horizontal intensity distribution was shaped with a cylindrical lens array to enlarge the horizontal to the divergent angle, and a specially-designed slanted shoulder to reduce the total internal reflection loss and extend the divergent angle from 45° to 67° with a flat-top shaping light pattern. As a result, only five pieces of the light emitting diode module around 6W is enough to build up a marine signal light to reach a distance of 8 nautical miles.

High-efficiency fluorescence collection for NV- center ensembles in diamond.

The negatively charged nitrogen vacancy (NV-) center ensembles in diamond have been demonstrated to be a promising platform for quantum metrology, but the poor fluorescence collection efficiency of a microscope objective limits the sensitivity of the NV- based sensors. Here we present a method for increasing the collected fluorescence intensity with a total internal reflection (TIR) lens. The detected fluorescence intensity is increased by approximately a factor of 56 compared with detection using a microscope objective with NA = 0.55, leading to a collection efficiency of 47.7% ± 3.1%. The signal-to-noise ratio is improved by a factor of 7.6 using the TIR lens. The proposed method is of great significance for collecting fluorescence from NV- centers in a large volume and can be used in weak fluorescence detection systems.

基于全内反射透镜二次配光的水下LED通信研究

基于全内反射透镜二次配光的水下LED通信研究

Surgical Lamp Design Based on LED Diffuse Transmission Illumination System

In this article, we have designed a surgical light lens especially for oral surgical illumination. It provides a uniform and wide field of view for illumination during oral surgery. The support system, a set of LEDs and a double free-form surface constituted the lighting system. The double free-form surface is composed of traditional free-form surface, designed total internal reflection lens and diffuse transmission plate, which improves the optical performance of the LED. When the light keeps dispersing the pupil constriction, it eventually causes our eyes to fatigue. The purpose of increasing diffuse transmission is to make the emitted light softer, thus making peoples’ eyes feel more comfortable. Based on the problems mentioned above, a numerical method is proposed as the basis for designing the double free-form surface. First, establishing a mathematical model based on the characteristics of the transmissive surface and the property of the LED. Henceforth, the nonlinear equations for the illumination distribution of the outside surface can be deduced. By solving the equation, the contour of the free-form surface is obtained. Later, we imported the contour into the 3D modeling software Solidworks to rotate so as to get the corresponding model. Finally, the simulation results suggest that the optical uniformity of the double free-form surface is able to reach as much as 86.18%.

LED-Based Collimating Line-Light Combining Freeform and Fresnel Optics

Illumination for line-scan machine vision systems is required to produce a highly asymmetric elliptical beam pattern, to maximize system speed and accuracy. The use of LED emitters with symmetric Lambertian emission patterns is challenging in this context, requiring significant beam reshaping. A design for a collimated line-light, with long working distance, utilizing LEDs with symmetric Lambertian emission patterns, is presented. Using a combination of Fresnel lenses and total internal reflection (TIR) optics, an elliptical beam with a high degree of collimation is achieved. TIR elements are designed based on an adaptation of a freeform lens design method published by Chen et al . [Opt. Express 20, 10 (2012)]. Practical performance of the design is verified experimentally using a prototype unit. In addition, the design is compared, using ray tracing software, to line-lights constructed using commercially available symmetric and elliptical TIR lenses, and its superior performance is confirmed. The optical design described is fully manufacturable and suitable for both small- and large-scale production.

High-flux focusable color-tunable and efficient white-light-emitting diode light engine for stage lighting

A color mixing light-emitting diode (LED) light engine that can replace 2-kW halogen–Fresnel spotlight with high-luminous flux in excess of 20,000 lm is reported for applications in professional stage and studio lighting. The light engine focuses and mixes the light from 210 LEDs of five different colors through a microlens array (MA) at the gate of O50 mm. Hence, it produces homogeneous color-mixed tunable white light from 3000 to 6000 K that can be adjustable from flood to spot position providing 10% translational loss, whereas the corresponding loss from the halogen–Fresnel spotlight is 37%. The design, simulation, and optimization of the light engine is described and compared to the experimental characterization of a prototype. The light engine is optimized through the simulated design of reflector, total internal reflection lens, and MA, as well as the number of LEDs. An optical efficiency of 59% and a luminous efficacy of 33 lm/W are achieved, which is three times higher than the 2-kW halogen–Fresnel spotlight. In addition to having color rendering of color rendering index Ra>85 and television lighting consistency index 12>70, the dimmable and tunable white light can be color controlled during the operational time.

Free-form surface design method for a collimator TIR lens.

A free-form (FF) surface design method is proposed for a general axial-symmetrical collimator system consisting of a light source and a total internal reflection lens with two coupled FF boundary surfaces. The profiles of the boundary surfaces are designed using a FF surface construction method such that each incident ray is directed (refracted and reflected) in such a way as to form a specified image pattern on the target plane. The light ray paths within the system are analyzed using an exact analytical model and a skew-ray tracing approach. In addition, the validity of the proposed FF design method is demonstrated by means of ZEMAX simulations. It is shown that the illumination distribution formed on the target plane is in good agreement with that specified by the user. The proposed surface construction method is mathematically straightforward and easily implemented in computer code. As such, it provides a useful tool for the design and analysis of general axial-symmetrical optical systems.

Design of asymmetrical total internal reflection optics with microstructures for lighting museum exhibits

A high-quality museum lighting system should demonstrate optimal color rendering and high light source efficiency. In addition, an adequate lighting management system is required for energy saving and visual comfort. However, symmetrical total internal reflection (TIR) lenses typically applied in lighting fixtures are inadequate for providing a comfortable lighting experience for museum visitors. This paper presents a new optical lens that forms a novel asymmetrical triangular light distribution for improving the vertical illuminance uniformity of museum exhibits. Moreover, the proposed lens can reduce the reflective glare caused by the glass covering exhibits. Monte Carlo ray tracing simulation techniques were used to develop various lens structures and numerous microstructures, which enabled changing the light distribution from a traditional symmetrical to an asymmetrical triangle. Finally, an asymmetrical TIR lens with a microstructure surface was constructed and applied to exhibit lighting. According to the ray tracing results obtained using Tracepro simulation software and DIALux lighting design software, the asymmetrical lens formed an asymmetrical triangular light distribution with an LED light source and enhanced the illuminance uniformity by 29 %, improving the light quality of museum exhibits. The preliminary simulation results revealed that the proposed lens structure effectively improved the LED lighting quality in the museum.

Design and optimization for total internal reflection collimators based on slope-error tolerance analysis

This work provides a design and optimization method for total internal reflection (TIR) lenses based on slope-error tolerance analysis. This work focuses on how the slope error impacts the central luminous intensity (CLI) of a TIR lens. The concentration standard index (CSI) is introduced as a metric for analyzing the CLI, both locally and globally. A unique design method for improved manufacturing tolerance is introduced, and a way of optimizing the TIR lens design in order to achieve a better slope-error tolerance is presented by evaluating the CSI. Using the design method, a TIR lens is fabricated and this theoretical approach is then demonstrated by a comparison between the tested contours of the TIR surfaces.

Innovative light collimator with afocal lens and total internal reflection lens for daylighting system.

This research presents a novel design of the collimator, which uses total internal reflection (TIR), convex, and concave lenses for the natural light illumination system (NLIS). The concept of the NLIS is to illuminate building interiors with natural light, which saves energy consumption. The TIR lens is used to collimate the light, and convex and concave lenses are used to converge the light to the required area. The results have shown that the efficiency in terms of achieving collimated light using the proposed collimator at the output of the light collector is better than that of a previous system without a collimator.

Color uniformity in spotlights optimized with reflectors and TIR lenses

We analyze the color uniformity in the far field of spotlight systems to estimate visual perception with a merit function derived from human factor experiments. A multi-colored light-emitting diode (LED) light engine with different light mixing levels is combined with several reflectors and total internal reflection (TIR) lenses. The optimized systems are analyzed at several color uniformity levels with regard to the efficiency, peak luminous intensity and dimensions. It is shown that these properties cannot all be optimized at the same time. Furthermore, excellent color uniformity can be reached by a light mixing layer in the light engine or by adding mixing elements to the secondary optics.

Design of optical system for collimating the light of an LED uniformly

A type of optical system consisting of one total internal reflection (TIR) lens and two reflectors is designed for collimating the light of an LED to a uniform pattern. Application of this kind of optical system includes underwater light communication and an underwater image system. The TIR lens collimates all the light of the LED to a nonuniform plane wavefront. The double-reflector system redistributes the plane wavefront uniformly and collimates again. Three optical systems that produce a different radius of the output light patterns are designed. The simulation result shows that the uniformity of the designed optical system is greater than 0.76, and the total output efficiency (TOE) is greater than 89%. At the same time, we conclude that the radius of the output reflector should not be smaller than that of the input reflector in order to keep high uniformity and TOE. One of the designed optical systems is fabricated by computer numeric control, and the experiment results satisfy that goal.

Goos-Hänchen shift in the miniaturized total internal reflection lens

For certain applications, total internal reflection (TIR) lenses are potentially more effective compared with refractive lenses and reflection mirrors since they permit more light power to go through the optical system. The efficiency of such lenses becomes even more prominent for miniature systems application where light absorption has negligible effect compared with the reflection losses at the interfaces. However, at such scales, the effect of Goos-Hänchen shift that associates the TIR should be accounted for in order to design a proper surface profile of the TIR lenses. It has been shown that a useful design that determines the total internal reflective surface profile can be obtained by solving an ordinary differential equation; such results facilitate realizing effective macro- and micro-scale lenses that are highly useful in integrated optics circuits and miniature optical systems.

Optimization of a total internal reflection lens by using a hybrid Taguchi-simulated annealing algorithm

In this paper, we propose a new method for optimization of a total internal reflection (TIR) lens by using a hybrid Taguchi-simulated annealing algorithm. The conventional simulated annealing (SA) algorithm is a method for solving global optimization problems and has also been used in non-imaging systems in recent years. However, the success of SA depends heavily on the annealing schedule and initial parameter setting. In this study, we successfully incorporated the Taguchi method into the SA algorithm. The new hybrid Taguchi-simulated annealing algorithm provides more precise search results and has lower initial parameter dependence.

Secondary optical element design for intracorporeal LED illumination system

In this Letter, we propose an intracorporeal illumination system for providing uniform and wide-field illumination during minimally invasive surgery. The illumination system is comprised of an Alexis wound retractor, a set of LEDs, and secondary optical elements (SOEs). The SOE was composed of a Fresnel lens and a total internal reflection lens, which was designed to improve the optical performance of the LED. The results of simulation demonstrate that the optical efficiency of each LED with an SOE could be increased from 33.6% to 82.9%. To avoid damage to human tissue by thermal effect, the number of LEDs with SOEs was optimized. The results indicate that our design to be applicable for practical surgery.