BreatheWithMe: Exploring Visual and Vibrotactile Displays for Social Breath Awareness during Colocated, Collaborative Tasks

Sharing breathing signals has the capacity to provide insights into hidden experiences and enhance interpersonal communication. However, it remains unclear how the modality of breath signals (visual, haptic) is socially interpreted during collaborative tasks. In this mixed-methods study, we design and evaluate BreatheWithMe, a prototype for...

Advancements in Spectral Power Distribution Modeling of Light-Emitting Diodes

The unique radiative, photometric and colorimetric characteristic of a light-emitting diode is derived from its spectral power distribution. Modeling such characteristics with respect to the forward current, temperature or operating time has been subject of various studies. Deriving a simple analytical model, however, is not trivial due to the...

The influence of phosphor particles on the water transport in optical silicones for LEDs

The reliability of LEDs decreases in moist environments. One potential gateway of moisture ingress, reducing the product lifetime is the lens. In white LEDs, phosphor particles are embedded into the optical silicone of the lens to convert the blue light emitted by the diode down in frequency and achieve a light output that appears white. In this...

Optimizing photon utilization in LED-based photocatalytic reactors

Photocatalysis involves the absorption of photons by a semiconductor to enhance chemical reactions. Examples of important applications include the degradation of hazardous chemicals, reduction of carbon dioxide to valuable chemicals and (partial) oxidation of hydrocarbons. Despite many successful demonstrations of this technology at lab-scale,...

Study on the Degradation of Optical Silicone Exposed to Harsh Environments

Degradation mechanisms of silicone plates under harsh environment conditions are studied in this investigation. Environmental degradation of silicone free form, used as secondary optics in Light Emitting Diode LED lighting lamps and luminaires or any other applications requiring high quality optics being used, has negative implications for the...

A review on discoloration and high accelerated testing of optical materials in LED based-products

Reduction of intensity of light output is one of the most common degradation modes in light-emitting diode (LED) systems. It starts from the failure of the various components in the system, including the chip, the driver, and optical components (i.e. phosphorous layer). The kinetics of degradation in real life applications is relatively slow...

Fluorescence imaging for whole slide scanning using LED-based color sequential illumination

In the field of pathology there is an ongoing transition to the use of Whole Slide Imaging (WSI) systems which scan tissue slides at intermediate resolution (0∼.25 μm) and high throughput (15mm²=min) to digital image files. Most scanners currently on the market are line-sensor based push-broom scanners for three-color (RGB)...

A novel lifetime prediction for integrated LED lamps by electronic-thermal simulation

In this paper, an integrated LED lamp with an electrolytic capacitor-free driver is considered to study the coupling effects of both LED and driver's degradations on lamp's lifetime. An electrolytic capacitor-less buck-boost driver is used. The physics of failure (PoF) based electronic thermal simulation is carried out to simulate the lamp's...

Monolithic 3D Wafer Level Integration: Applied for Smart LED Wafer Level Packaging

LED standardization in China and South East Asia: Stakeholders, infrastructure and institutional regimes

LED is now becoming the new standard in lighting solutions in developed countries. However, in developing countries, it is not yet used on a large scale. One of the reasons is a lack of established regional standards for LED. An institutional infrastructure for standardization is one of the essential elements for the establishment of common...

Reliability and Lifetime Prediction of Remote Phosphor Plates in Solid-State Lighting Applications Using Accelerated Degradation Testing

A methodology, based on accelerated degradation testing, is developed to predict the lifetime of remote phosphor plates used in solid-state lighting (SSL) applications. Both thermal stress and light intensity are used to accelerate degradation reaction in remote phosphor plates. A reliability model, based on the Eyring relationship, is also...

Reliability and Lifetime Prediction of Remote Phosphor Plates in Solid-State Lighting Applications Using Accelerated Degradation Testing

A methodology, based on accelerated degradation testing, is developed to predict the lifetime of remote phosphor plates used in solid-state lighting (SSL) applications. Both thermal stress and light intensity are used to accelerate degradation reaction in remote phosphor plates. A reliability model, based on the Eyring relationship, is also...

Integrated Automotive High-Power LED-Lighting Systems in 3D-MID Technology

The growing energy consumption of lighting as well as rising luminous efficacies and -fluxes of high-power Light Emitting Diodes (LEDs) have contributed to the widespread use of LEDs in modern lighting systems. One of the most prominent users of the LED-technology is automotive (exterior) lighting. It benefits from LEDs’ high efficiencies and...

How does a LED lamp work?

The liberation of light

For more than a century, light has come from glass shell. But it won’t for much longer, believes Prof. GQ (Kouchi) Zhang. “Light emitting diodes are going to liberate light.”

Compact collimators for high brightness blue LEDs using dielectric multilayers

A novel method is presented to inject the light of millimeter-sized high-brightness blue LEDs into light guides of submillimeter thickness. Use is made of an interference filter that is designed to pass only those modes that will propagate in the light guide by total internal reflection. Other modes are reflected back to the LED cavity and...

Rigorous simulations of emitting and non-emitting nano-optical structures

In the next decade, several applications of nanotechnology will change our lives. LED lighting is about to replace the common light bulb. The main advantages are its energy efficiency and long lifetime. LEDs can be much more efficient, when part of the emitted light that is currently trapped in the device, could be radiated out of the device....

Evaluation of LED application in general lighting