Abstract: An ultraviolet light detector for detecting levels of ultraviolet light in a liquid disinfection unit comprises two solid state silicon photodetectors. A first photodetector generates a photo-induced current proportional to the amount of visible, infra-red, and ultraviolet light emitted. A second photodetector generates a photo-induced current proportional to the amount of visible and infrared light emitted. The photodetectors are electrically connected in reverse parallel, generation an output current equal to the difference between the photo-induced currents of the photodetectors. The output current is thus proportional to the UV light intensity. The output current may be converted into a voltage, which may be monitored to ensure that the ultraviolet light intensity is sufficient for complete disinfection of the liquid. An electronic control system may be provided so that the output voltage controls a solenoid valve and/or an alarm in the disinfection unit.

Abstract: A lens for a light emitting diode (LED) lamp is formed as two ellipses rather than as one. The ellipses are axially symmetric and are translated away from the optical axis with each ellipse having a focus located on the LED chip away from the central bond pad so that the bond pad shadow does not decrease on-axis light intensity. In alternative embodiments, the depression located at the intersection of the two ellipses is flattened and the axes of the two ellipses are translated away from the optical axis and are also tilted.

Abstract: The principles of non-imaging optics, rather than imaging optics, are used to provide a high power LED illumination lamp that has a specified limited viewing angle. A compound parabolic flux extractor extracts and concentrates light emitted by an LED chip and a light pipe continues the concentration into the specified viewing angle. A lens or a diffusant may be used to modify the light output of the lamp. A light constructed as an array of the lamps is suitable for use as an automobile external light such as a center high mounted stop light.