Design Of Illumination Systems Research Articles

Focus on software, data acquisition, and instrumentation

Focus on software, data acquisition, and instrumentation

Development of Recommendations for Catering Industry Illumination Systems

The article describes development of the set of recommendations concerning design and modernisation of illumination systems for catering industry. Relevant publications were studied, a number of parameters of illumination systems and colour layouts of catering outlets were reviewed, three scenarios of restaurant illumination were modelled, a questionnaire was developed and potential restaurant visitors (of different gender and age) were surveyed, and the summarised list (set) of recommendations to be used in design of catering outlets was formed.

LED light design method for high contrast and uniform illumination imaging in machine vision.

In machine vision, illumination is very critical to determine the complexity of the inspection algorithms. Proper lights can obtain clear and sharp images with the highest contrast and low noise between the interested object and the background, which is conducive to the target being located, measured, or inspected. Contrary to the empirically based trial-and-error convention to select the off-the-shelf LED light in machine vision, an optimization algorithm for LED light design is proposed in this paper. It is composed of the contrast optimization modeling and the uniform illumination technology for non-normal incidence (UINI). The contrast optimization model is built based on the surface reflection characteristics, e.g.,the roughness, the reflective index, and light direction, etc., to maximize the contrast between the features of interest and the background. The UINI can keep the uniformity of the optimized lighting by the contrast optimization model. The simulation and experimental results demonstrate that the optimization algorithm is effective and suitable to produce images with the highest contrast and uniformity, which is very inspirational to the design of LED illumination systems in machine vision.

Design of Ergonomic Illumination Systems for Cultural, Medical, Educational Facilities

Design of Ergonomic Illumination Systems for Cultural, Medical, Educational Facilities

Design of an Effective Illumination System for an Opencast Coal Mine

The scientific work documented in this article was carried out, as a part of the research investigation sponsored by a major coal company, to create a safe visual working environment for a mechanized opencast coal mine by designing an effective illumination system. It included an illumination survey of the existing lighting system in various working areas of the mine in which, the existing illuminance levels were found inadequate in most of the work places and hence an effective and modified design of the illumination system was necessary. The improvement measures were carried out by analysis of the problem, which leaded to the design of illumination system using DIALux software. DGMS standard for opencast mine lighting was used for both assessment and design of illumination systems. Haul road lighting design was performed as per CIE EN 13201 standard, which is internationally used for road lighting. The design model resulted in significant improvement over the existing system and all the standards were met as per the DGMS guidelines.

Phase space optics: an alternate approach to freeform optical systems

Freeform optical surfaces are of increasing interest in the design of modern imaging and illumination systems. However for the optical designer there are still methods missing in order to illustrate and quantify the effect of freeform surfaces in terms of aberrations or their impact on illumination performance. Phase space optics might offer an alternative way to understand freeform optics and their impact within optical systems. To prove this, phase space in geometrical optics is generally introduced, and some example systems are presented which allow us to relate phase space transformations to geometrical aberrations. In this way, we show that aberrations can be understood as nonlinear deformations of phase space, which need to be minimized in imaging designs or to be employed for homogenizing radiation in illumination designs.

Developing Daisy Chain Receivers for Light-Emitting Diode Illumination Adopting the Digital Multiplex-512 Protocol

Protocol for digital multiplex with 512 pieces of information is increasingly adopted in the design of illumination systems. In conventional light-emitting diode systems, the receivers are connected in parallel and each of the receiving units receives all the data from the master dimmer console, but each receiving unit operates by recognizing as its own data that which corresponds to the assigned number of the receiver. Because the serial numbers of illumination devices are transmitted in binary code, synchronization is too complicated to be used properly. In order to improve the protocol of illumination control systems, we propose an algorithm of protocol reception to install and manage the system in a simpler and more convenient way. We propose the systems for controlling the light-emitting diode illumination of simplified receiver slaves adopting the digital multiplex-512 protocol where master console and multiple receiver slaves are connected in a daisy chain fashion. The digital multiplex-512 data packet is received according to the sequence order of their locations from the console, without assigning the sequence number of each channel at the receiving device. The purpose of this paper is to design a simple and small-sized controller for the control systems of lamps and lighting adopting the digital multiplex-512 network.

Automatic design of illumination systems

The approach for autodesign of optical characteristics of different illumination units such as backlight systems, led arrays and light boxes is considered. Suggested software solution allows finding optimal configuration of lighting scheme for providing necessary distribution of output light. Additional preprocessing phase is introduced in design process, which provides reduction of design iterations and better convergence compared to conventional design methods, utilizing random fluctuations of design parameter between iterations. The results of several designs of different kinds of illumination systems are presented.

Effects of Current Modulation Conditions on the Chromaticity of Phosphor Converted (PC) White LEDs

For two well-known modulation methods, stepwise current modulation (SCM) and pulse width modulation (PWM), the effects of driving current modulation conditions on chromaticity were experimentally investigated in a white LED lighting system. For the experimental implementation of both SCM and PWM, a white LED lighting was fabricated using phosphor converted (PC) white light emitting diodes (LEDs) and a driving circuit module was developed. By using them, the variations of illuminance, color coordinates, and spectrum were evaluated under various forward current conditions. Through the analysis in color coordinates, yellow shift in SCM and blue shift in PWM were observed on chromaticity diagrams with increasing average driving current. In addition, in order to analyze color deviation quantitatively, color distance before and after current increase, and the correlated color temperature (CCT) were calculated. As a result, for the white LED lighting in both modulation conditions, the maximum difference in the calculated CCT was obtained close to 1000 K. It means that careful consideration is required to be taken in the design of illumination systems to avoid serious problems such industrial accidents.

Investigation of Prismatic Daylight Collectors With Different Apexes

Prismatic elements are widely used in daylight illumination systems. The characteristics of the light that emerges from the surface of a right-angled prism vary with the apex of the prism and the incident angle of the sunshine illuminating the surface of the prismatic daylight collector. This paper investigates the effect of the apex angle of a right-angled prismatic collector on the performance of the collector using a matrix ray-tracing model and the edge principle. It was found that the majority of the light emerges from the hypotenuse of the right-angled prism when sunshine is incident on the surface of the prismatic daylight collector; furthermore, the flux of the light emerging from the hypotenuse that directs illuminating space decreases as the apex of the right-angled prism is increased. The intensity distribution of the majority of the light emerging from the hypotenuse of a right-angled prism can be used to guide the design of natural light illumination systems and enhance their performance. The percentage of light emerging from the hypotenuse decreases with the number of prismatic elements because the relative area of the emerging light that reaches the adjacent prism increases with the number of prismatic elements. The analysis of the relative area of the hypotenuse, where the emerging light that reaches the adjacent prism according to the edge ray principle shows that the total area is constant when the number of prismatic elements is greater than 10; an economical prismatic daylight collector can be realized with less material due to the larger number of smaller prisms with the same apex.

Availability of luminous flux below a bended light-pipe: Design modelling under optimal daylight conditions

To quantify an averaged directionality of light beams transmitted by hollow light guides the asymmetry parameter has been introduced which is computed from the luminous intensity solid or curve. In many situations, the light guides with upper part elbowed toward the Southern sky are able to collect more light than a corresponding straight pipe. However, under different sunlight and skylight conditions the internal reflections are more complex, resulting in a large variety of light-pipe efficiency. A more realistic prediction of the luminous intensity solid under manifold exterior daylight conditions is significant for the optimal design and installation of passive illumination systems using bended light guides. Here, the orientation of the elbow is crucial for an efficient utilization of daylight, especially during a clear day. This study documents that the maximum efficiency of the bended light-pipe is reached when its upper part is pointed nearby the sun position but directly towards the sun.

LED-Based Projection Systems

A novel design methodology for LED-array-based projection displays has been developed. By combining etendue limitation, system intensity, and efficiency requirements, a novel parameter space is proposed. Using this parameter space, LED lens-array and compound parabolic concentrator (CPC)-array illumination systems have been designed. A 1000-lm LED light source is built. Based on these lens-array and CPC-array illuminators, several LED-based liquid crystal on silicon (LCOS) projection systems are suggested. Among them, a one-panel LCOS projection system is proposed and tested. The method discussed here should be useful in the design of LED-array illumination systems for projectors in general.

Design of haul road lighting system. Part III: application

The design of haul road illumination systems based on a scientific approach is very important. Improperly planned lighting systems may provide unsatisfactory illumination and may also incur higher costs. This paper describes illumination systems designed for two haul roads using the computer programs developed in earlier stages of this work. System performances and cost are compared with the existing illumination system. Designs based on the developed programs show total potential cost savings of approximately 26% and 48% for the two systems.

Simplex optimization method for illumination design

A modified simplex optimization method is developed for the design of illumination systems. The simplex method is a judicious choice for illumination optimization because of its robustness and convergence properties. To optimize the simplex method, its four parameters are adjusted dependent on the dimensionality of the space to converge with fewer iterations. This work is presented for the end game, when the optimizer is converging on a local optimum rather than searching for it. Up to a 37% reduction in the number of computations is realized. An example using a compound parabolic concentrator is compared between the standard and the modified simplex methods, providing over 22% improvement in the end game.

Focus on Software

Focus on Software

Analytical model of flux propagation in light-pipe systems

An analytical model of light propagation in rectangular light pipes, termed the flux confinement diagram (FCD), is developed. Based on the edge ray concept of nonimaging optics, the FCD is a construction that describes the angular distribution of flux propagating in a light pipe depending on a light pipe's index of refraction and its geometry. With the FCD model, the angular "mode" of a ray can be defined at any plane in the system. The FCD model is developed here and used to describe flux input coupling, transport, and output coupling in light-pipe illumination systems. The practical example of a flux loss prediction due to a geometrical change (a bend) is examined using the FCD and compared to a ray-tracing analysis. We discuss how this model of flux propagation is a useful tool to aid in "first-order" design and layout of light-pipe illumination systems.

Optical design with parametrically defined aspheric surfaces

The standard aspheric surface definition has been used successfully to correct aberrations in a wide variety of systems. However, in some current applications a more general surface definition is needed. We present a more general approach that uses parametrically defined optical surfaces for the optical design of imaging and illumination systems.

Use of implicitly defined optical surfaces for the design of imaging and illumination systems

This paper presents an approach that uses implicitly defined optical surfaces for designing imaging and illumination systems. In the standard aspheric optical surface, consisting of a conic with an even- order polynomial, the surface sagitta (sag), z, is defined explicitly as a function of the coordinates x and y. This standard aspheric surface is deemed useful for describing surfaces with small departures from a conic surface. However, optical surfaces with large departures from a conic are sometimes useful for current applications, such as null certification, conformal domes and windows, luminaires, and condenser design. The approach in this paper, which uses implicitly defined surfaces to describe highly aspheric surfaces, can be more general and easier to use for some situations. The sag z of an implicit surface is not defined directly, as it is in an explicit surface. Instead, it is defined indirectly in a more general form, as a function of x, y, and z. Because implicit functions have a more general form than explicit functions, they can better describe a variety of surfaces that cannot be easily described using the standard explicit aspheric surface. We show some examples of current interest.

Software development for design of illumination systems

Optical design software is developed that includes the capability to model illumination systems. The software enables predicting the intensity distribution of radiation at a plane located at some distance from the source. An illumination system comprising an ellipsoidal reflector and a spherical source is modeled and the results of the analysis are compared to those achieved experimentally.

Theoretical model of visible radiation from rare gas flashlamps

A simple theoretical model of visible light emission from xenon flashlamps is presented. The continuum light emission is calculated from the rate of electron-ion recombination in the xenon plasma, which is treated as a greybody in thermal equilibrium. The effect of radiation reabsorption is calculated in terms of the temperature-dependent greybody emissivity. The model predictions of radiated power and energy are compared to measured data. Reasonable agreement is obtained over a wide range of parameters of practical interest. Thus the model provides a useful analytical tool for first-order engineering design of xenon flash-lamp illumination systems.