Applications of uv leds for disinfection

Abstract

A variety of applications for UV LEDs that are integrated into a system are described, where the UV light is used for disinfection of air or surfaces, or used to detect the scattering light by particles, or used for skin treatment. In one embodiment, the UV light from the UV LEDs is generated internal to a housing and is optically coupled to a transparent or translucent surface touched by the human finger, such as a touch screen, a fingerprint scanner, backlit buttons or keys, a toggle of a light switch, a door knob, etc. The UV light is emitted through the touched surface to periodically disinfect the surface. A visual indication of the UV LEDs being energized is provided for safety, such as energizing visible light LEDs or a phosphor on a portion of the touched surface.

What is claimed is: 
     
         1 . A system containing an integral disinfection apparatus comprising:
 a first article having a transparent or translucent surface that is touched by a human finger;   one or more light emitting diodes (LEDs) emitting ultraviolet (UV) light in the range of UVB or UVC;   a housing supporting the first article and containing the LEDs, wherein the UV light from the LEDs is optically coupled from inside the housing to an outer surface of the first article to at least partially disinfect the surface of the first article that is touched by the human finger; and   a timing circuit for automatically controlling the LEDs to be intermittently energized.   
     
     
         2 . The system of  claim 1  further comprising a visible light emitter within the housing that emits visible light only when the LEDs emit the UV light. 
     
     
         3 . The system of  claim 1  wherein the UV light from the LEDs is optically coupled to an edge of the first article, and the first article acts as a light guide to guide the UV light to the surface that is touched by the human finger. 
     
     
         4 . The system of  claim 3  wherein the first article is a touch screen layer over a display device. 
     
     
         5 . The system of  claim 3  wherein the system is a fingerprint detector having an imager that detects a fingerprint of the human finger while touching the first article. 
     
     
         6 . The system of  claim 1  wherein the first article comprises backlit buttons or keys touched by the human finger, the system further comprising:
 a backlight for the buttons or keys, wherein the light from the backlight includes both visible light and the UV light. 
 
     
     
         7 . The system of  claim 6  wherein the UV light from the LEDs is optically coupled to an edge of the backlight, and the backlight acts as a leaky light guide. 
     
     
         8 . The system of  claim 1  wherein the LEDs emitting UV light are UV LEDs, the system further comprising one or more visible light LEDs, wherein the UV light from the UV LEDs and the visible light from the visible light LEDs are both optically coupled to the first article. 
     
     
         9 . The system of  claim 8  wherein the visible light LEDs are only energized when the UV LEDs are energized. 
     
     
         10 . The system of  claim 8  wherein the visible light LEDs are energized even when the UV LEDs are not energized. 
     
     
         11 . The system of  claim 1  further comprising a material that emits visible light when energized by the UV light to visually indicate that the LEDs are energized. 
     
     
         12 . The system of  claim 11  wherein the material is a phosphor deposited on the first article. 
     
     
         13 . The system of  claim 1  wherein the first article is a toggle of a light switch module. 
     
     
         14 . The system of  claim 13  wherein a material on the surface of the toggle emits visible light when energized by the UV light to visually indicate that the LEDs are energized. 
     
     
         15 . The system of  claim 1  further comprising a controller that detects when the first article is not being touched by the human finger, wherein the controller controls the timer to energize the LEDs when the controller detects that the first article is not being touched. 
     
     
         16 . The system of  claim 1  wherein the first article is a door knob housing the LEDs. 
     
     
         17 . A method of automatically and periodically disinfecting a transparent or translucent surface of a first article that is touched by a human finger, the method comprising:
 providing one or more light emitting diodes (LEDs) emitting ultraviolet (UV) light in the range of UVB or UVC in a housing, where the housing also supports the first article;   controlling a timing circuit to automatically energize the LEDs when it is determined that the first article is not being touched by the human finger; and   optically coupling the UV light from the LEDs from inside the housing to an outer surface of the first article to at least partially disinfect the surface of the first article that is touched by the human finger.   
     
     
         18 . The method of  claim 17  further comprising providing a visual indication that the LEDs are energized. 
     
     
         19 . The method of  claim 17  wherein the step of providing a visual indication that the LEDs are energized comprises energizing one or more visible light LEDs along with the LEDs that emit the UV light. 
     
     
         20 . The method of  claim 17  wherein the step of providing a visual indication that the LEDs are energized comprises energizing a phosphor that is deposited on the first article.