Patent attributes
A handheld light assembly for eradicating pathogens includes a housing. A processor and a lamp are disposed inside the housing. The lamp irradiates surfaces with disinfecting ultraviolet light having a peak wavelength of 222 nm filtered to restrict illumination to between 200 nm and 230 nm within an irradiation zone. A distance measuring system includes a secondary light source generating secondary light and a photodetector for measuring distance of the secondary light to a surface being irradiated by the lamp light being reflected from the surface to the photodetector. The secondary light source is offset at an angle from the lamp thereby projecting the light beam to a central area of the irradiation zone generated by the lamp. The photodetector signals the processor to calculate a vertical distance between the lamp and the central area of the irradiation zone on the surface being irradiated from an angular projection of the secondary light.
