Manufacturing and measurement of freeform optics

Methods for fabricating light emitting diode (LED) chips comprising providing a plurality of LEDs typically on a substrate. Pedestals are deposited on the LEDs with each of the pedestals in electrical contact with one of the LEDs. A coating is formed over the LEDs with the coating burying at least some of the pedestals. The coating is then planarized to expose at least some of the buried pedestals while leaving at least some of said coating on said LEDs. The exposed pedestals can then be contacted such as by wire bonds. The present invention discloses similar methods used for fabricating LED chips having LEDs that are flip-chip bonded on a carrier substrate and for fabricating other semiconductor devices. LED chip wafers and LED chips are also disclosed that are fabricated using the disclosed methods.

Wafer level phosphor coating method and devices fabricated utilizing method

Innovation in concentrated solar power

This work focuses on innovation in CSP technologies over the last decade. A multitude of advancements has been developed during this period, as the topic of concentrated solar power is becoming more mainstream. Improvements have been made in reflector and collector design and materials, heat absorption and transport, power production and thermal storage. Many applications that can be integrated with CSP regimes to conserve (and sometimes produce) electricity have been suggested and implemented, keeping in mind the environmental benefits granted by limited fossil fuel usage.

Innovation in Concentrated Solar Power

Advanced solar energy utilization technology requires high-grade energy to achieve the most efficient application with compact size and least capital investment recovery period Concentrated solar power (CSP) technology has the capability to meet thermal energy and electrical demands Benefits of using CSP technology with parabolic trough collector (PTC) system include promising cost-effective investment, mature technology, and ease of combining with fossil fuels or other renewable energy sources This review first covered the theoretical framework of CSP technology with PTC system Next, the detailed derivation process of the maximum theoretical concentration ratio of the PTC was initially given Multiple types of heat transfer fluids in tube receivers were reviewed to present the capability of application Moreover, recent developments on heat transfer enhancement methods for CSP technology with PTC system were highlighted As the rupture of glass covers was frequently observed during application, methods of thermal deformation restrain for tube receivers were reviewed as well Commercial CSP plants worldwide with PTC system were presented, including those that are in operation, under construction, and announced Finally, possible further developments of CSP plants with PTC system were outlined Besides, suggestions for future research and application guidance were also illustrated

Progress in concentrated solar power technology with parabolic trough collector system: A comprehensive review

Introduction to Nonimaging Optics covers the theoretical foundations and design methods of nonimaging optics, as well as key concepts from related fields. This fully updated, revised, and expanded Second Edition: 

Features a new and intuitive introduction with a basic description of the advantages of nonimaging optics
Adds new chapters on wavefronts for a prescribed output (irradiance or intensity), infinitesimal etendue optics (generalization of the aplanatic optics), and Kohler optics and color mixing
Incorporates new material on the simultaneous multiple surface (SMS) design method in 3-D, integral invariants, and etendue 2-D
Contains 21 chapters, 24 fully worked and several other examples, and 1,000+ illustrations, including photos of real devices
Addresses applications ranging from solar energy concentration to illumination engineering
Introduction to Nonimaging Optics, Second Edition invites newcomers to explore the growing field of nonimaging optics, while providing seasoned veterans with an extensive reference book.

Introduction to Nonimaging Optics

An optical manifold for efficiently combining a plurality of LED outputs into a single, substantially homogeneous output, in a small, cost-effective package. The optical manifolds can be used to combine multiple LEDs of the same color and provide a high intensity output aperture with very high uniformity and sharp borders, or they can be used to generate a multiwavelength output, such as red, green, and due LEDs that are combined to generate white light. Embodiments are also disclosed that use a single or multiple LEDs and a remote phosphor and an intermediate wavelength-selective filter arranged so that backscattered photoluminescence is recycled to boost the luminance and flux of the output aperture. The optical manifolds are designed to alleviate substantial luminance inhomogeneities inherent to LEDs. The optical manifold utilizes principles of non-imaging optics to transform light and provide directed, substantially uniform light sources.

Optical manifold for light-emitting diodes

The simultaneous multiple surface (SMS) method in 3-D geometry is presented. Given two orthotomic input ray bundles and another two orthotomic output ray bundles, the method provides an optical system with two free-form surfaces that deflects the rays of the input bundles into the rays of the corresponding output bundles and vice versa. In nonimaging applications, the method enables controlling the light emitted by an extended light source much better than single free-form-surface designs, and also enables the optics contour to be shaped without efficiency losses. The method is also expected to find applications in imaging optics.

Simultaneous multiple surface optical design method in three dimensions

An optical device for coupling the luminous output of a light-emitting diode (LED) to a predominantly spherical pattern comprises a transfer section that receives the LED's light within it and an ejector positioned adjacent the transfer section to receive light from the transfer section and spread the light generally spherically. A base of the transfer section is optically aligned and/or coupled to the LED so that the LED's light enters the transfer section. The transfer section can comprises a compound elliptic concentrator operating via total internal reflection. The ejector section can have a variety of shapes, and can have diffusive features on its surface as well, including a phosphor coating. The transfer section can in some implementations be polygonal, V-grooved, faceted and other configurations.

Optical device for LED-based lamp

In order to achieve competitive system costs in mass-production, it is essential that CPV concentrators incorporate sufficient manufacturing tolerances. This paper presents an advanced concentrator optic comprising a Fresnel lens and a refractive secondary element, both with broken rotational symmetry, an optic producing both the desired light concentration with high tolerance (high acceptance angle) as well as an excellent light homogenization by Kohler integration. This concentrator compares well with conventional Fresnel-based CPV concentrators.

Julio Chaves

Papers

Introduction to Nonimaging Optics

Optical manifold for light-emitting diodes

Simultaneous multiple surface optical design method in three dimensions

Optical device for LED-based lamp

High performance Fresnel-based photovoltaic concentrator