Hyperparabolic concentrators

We present a family of three-dimensional concentrators constructed from the photic field generated by a Lambertian emitter. The profile of these concentrators is obtained from the field lines for a two-dimensional truncated wedge and is based on the union between a hyperbola and a tilted parabola. By revolution of this profile, we obtain hyperparabolic concentrators (HPCs). In the limiting case when the focal length of the hyperbola becomes the radius of the exit aperture, the HPC becomes the well-known compound parabolic concentrator. On the other hand, when the focal length of the hyperbola becomes infinite, the HPC achieves the thermodynamic limit of concentration

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In Memoriam Jesús Manuel Zoido Chamorro (1964-2010)

Recoge documentos, relatos y testimonios de los compañeros y amigos de Jesús Manuel Zoido Chamorro

Planar optical array with a spatial-integration feature

A planar optical array is presented that provides a selective concentration of the light incident upon the system onto a given area. Several alternative designs are analyzed and explained geometrically. The photometric calculation is presented for three different levels of approximation. A prototype of the proposed system is tested, showing good accordance with the theoretical predictions

Analytical method to measure bending deformations in prismatic optical films

The aim of this work is to provide an analytical method based on experimental measurements in order to obtain the prismatic film deformation for different curvatures of Hollow Cylindrical Prismatic Light Guides (CPLG). To conform cylindrical guides is necessary bend the film to guide the light, changes induced by curving the film give rise to deformation shifts. Light losses affected by deformation has been experimentally evaluated and numerically analyzed. The effect of deformation in prism angle is specially increased for CPLG of curvatures higher than 20 m-1. An experimental method for accurate transmittance measurements related to bending is presented

Improved and customized secondary optics for photo-voltaic concentrators

In this contribution the line flow method is applied to an optimized secondary optics in a photovoltaic concentration system where the primary optics is already defined and characterized. This method is a particular application of photic field theory. This method uses the parameterization of a given primary optics, including actual tolerances of the manufacturing process. The design of the secondary optics is constrained by the selection of primary optics and maximizes the concentration at a previously specified collection area. The geometry of the secondary element is calculated by using a virtual source, which sends light in a first concentration step. This allows us to calculate the line flow for this specific case. This concept allows designing more compact and efficient secondary optics of photovoltaic systems

Thermal influences on optical properties of light-emitting diodes: a semiempirical model

The application of LED technology to fields such as alphanumerical displays and traffic control is continuously increasing. Because the technology is used outdoors, it must be able to operate under various environmental conditions. Like all semiconductor devices, LED’s have properties that change with temperature. We propose a semiempirical model, based on semiconductor solid-state theory, that predicts the changes in the emission spectrum including the effect of temperature changes on the optical properties of the LED, within a range appropriate for outdoor applications (0–40 °C). This model permits us to evaluate the changes in the output flux and the chromaticity coordinates of the LED. We checked this model with seven different LED’s

Beacon system based on light-emitting diode sources for runways lighting

New aeronautical ground lighting techniques are becoming increasingly important to ensure the safety and reduce the maintenance costs of the plane's tracks. Until recently, tracks had embedded lighting systems whose sources were based on incandescent lamps. But incandescent lamps have several disadvantages: high energy consumption and frequent breakdowns that result in high maintenance costs (lamp average life-time is similar to 1500 operating hours) and the lamp's technology has a lack of new lighting functions, such as signal handling and modification. To solve these problems, the industry has developed systems based on light-emitting diode (LED) technology with improved features: (1) LED lighting consumes one tenth the power, (2) it improves preventive maintenance (an LED's lifetime range is between 25,000 and 100,000 hours), and (3) LED lighting technology can be controlled remotely according to the needs of the track configuration. LEDs have been in use for more than three decades, but only recently, around 2002, have they begun to be used as visual aids, representing the greatest potential change for airport lighting since their inception in the 1920s. Currently, embedded LED systems are not being broadly used due to the specific constraints of the rules and regulations of airports (beacon dimensions, power system technology, etc.). The fundamental requirements applied to embedded lighting systems are to be hosted on a volume where the dimensions are usually critical and also to integrate all the essential components for operation. An embedded architecture that meets the lighting regulations for airport runways is presented. The present work is divided into three main tasks: development of an optical system to optimize lighting according to International Civil Aviation Organization, manufacturing prototype, and model validation