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We report an intuitive approach to simulating the performance of the phosphor-based light emitting diode (LED) by using the two-light-sources model for an optimized LED lens. The optimized secondary lens shape is achieved by approaching a uniform energy distribution on the detecting plane. Both the spectrum and spatial apodization of the LED structure are discussed, and the results indicate that the two-light-sources model can solve the misleading design on the phosphor-based LED due to imperfect color mixing of light source, that one can satisfy the highly uniformity requirement for specific applications, such as display backlight or optogenetic.

We present a cost-effective optogenetic experimental setup for investigation of synaptic gating (neuron gate). The setup consists of a cell illuminating system containing a common micro-display of a commercial word processor and light emitting diode (LED) semiconductor materials instead of optogenetic cells. The performance is verified by illuminating the LED materials and measuring the induced electric potential.

Light emitting diode (LED) has more advantages compared with a traditional incandescent light bulb and a fluorescent lamp, such as small size, low quantity of heat, long life, low power consumption, fast response, plain packaging and ease of develop ment of a frivolous short product. A methodology is proposed to improve the uniformity of the LED illumination system. As a light source in a backlight unit (BLU), the requirement for optical characteristics of a LED is different from highly directional conventional ones. New diffused-type LEDs need to be developed to fulfill the requirement of the BLU industry. A non-spherical lens is designed to optimize uniformity, and a great improvement in uniformity from 28.4 to 64% is demonstrated. In the future, it may used in an LED display to improve the unevenness of illumination.

There are many reasons that can degrade the image quality performance in a projection system, such as environment temperature, MTF of projection lens, structure of Lcd panel, EMI on the PCB and driver scheme... etc. Image quality is a function of all these parameters. In this article, the authors would like to estimate the image quality of a projection system under driver schemes and design parameters from the system point of view. The relationships between the voltage difference applied on liquid crystal (LC) cell and defect phenomenon are also revealed. This gives a clear-cut for different image defect (ex: flicker) and its causality. In the present time, ITRI/OES were modeling the LCOS Panel pixel with SpiceTM and ASAPTM for the estimation of image quality during the design of the optical engine.© (2002) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Liquid crystals have been recognized as practical adaptive optical components for imaging and nonimaging applications. We have studied a liquid crystal lens without power modulation, as distinct from a focus modulating lens, and have simulated the effects of transient birefringence on the energy distribution on the focal plane. Our results indicate that owing to the particular transient spreading energy patterns on the focal plane, a focusing reversal phenomenon takes place during the operation of this lens, and the characteristic of the modulation transfer function (MTF) of this device indicates that this lens can serve as a spatial frequency filter.