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The primary goal of a vehicular headlight is to improve safety in low-light and poor weather conditions. The typical headlight however has very limited flexibility - switching between high and low beams, turning off beams toward the opposing lane or rotating the beam as the vehicle turns - and is not designed for all driving environments. Thus, despite decades of innovation in light source technology, more than half of the vehicular accidents still happen at night even with much less traffic on the road. We will describe a new DMD-based design for a headlight that can be programmed to perform several tasks simultaneously and that can sense, react and adapt quickly to any environment with the goal of increasing safety for all drivers on the road. For example, we will be able to drive with high-beams without glaring any other driver and we will be able to see better during rain and snowstorms when the road is most treacherous to drive. The headlight can also increase contrast of lanes, markings and sidewalks and can alert drivers to sudden obstacles. In this talk, we will lay out the engineering challenges in building this headlight and share our experiences with the prototypes developed over the past two years.

In this article we will introduce a Light Emitting Diode (LED) lighting diffuser plate which diffuses light by optical microstructure. In LED lighting, LED array is the most popular method to attain the illuminance requirement, but this method will produce the glaring and non-uniform illuminance problems. Traditionally, diffuser, which is comprised of diffuser particles, is used to solve the above problems, but it also produces another problem which is low lighting efficiency. Therefore, we use optical microstructure to replace the diffuser particles to solve the problems of LED lighting but only reduce a little lighting efficiency. Moreover, we could control the lighting area of the LED lamp by designing the optical microstructure.

The recommended by the CIE method of the discomfort glare evaluation demands the knowledge of the luminance distribution in interior, size and location of each glaring area. These quantities can be pointed out of measurements conducted by means of superficial detector. Received map of luminance distribution must be numerically analyzed.

Bright light can temporarily reduce the visual capacity of the human eye. Especially in traffic or in dealing with lasers disability glare can considerably reduce the visual faculty and lead to accidents. Even after the glare light has disappeared out of the field of vision, the visual capacity can still remain reduced for seconds or even minutes. It is therefore indispensable to investigate the recovery time of the human eye after glaring and to determine limiting exposures in order to avoid accidents or possible eye damage. We report on measurements of the recovery time in the range from 475 nm to 650 nm performed with thermal sources. Experiments are reported on the influence of varying intensities of test and glare light applied in the line of sight or extrafoveally. These studies allow us to give an empirical formula for the recovery time. In the present contribution we also report on measurements as a function of the duration of glaring. The range from 20 microsecond(s) to 1 s has been covered with an Argon laser at 488 nm as glare source. The resulting recovery time in different regions of this very large time scale will be discussed.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The influence of intraocular light scatter on letter identification in the absence and presence of glaring light is studied through computer simulations and simple experiments on healthy test subjects wearing diffusive glasses with known light scattering properties. An explicit expression for the point-spread function of a cataractous eye is used to calculate retinal images. For estimating resolution in the calculated images an assumed neural contrast sensitivity function is needed. The function used is derived from measurements by Campbell and Green. Experimental results are in agreement with theory. The analysis shows that visual acuity is quite insensitive even to substantial diffusive scattering provided that glare sources are not present in the field of view. Comparing measurements of `letter size' with measurements of `letter contrast' the latter method is found to measure intraocular light scattering more sensitively.