RETROREFLECTIVE ARTICLES AND DEVICES HAVING VISCOELASTIC LIGHTGUIDE

摘要

Disclosed herein is an optical device having a light source, a viscoelastic lightguide and a retroreflective film suitable for retroreflecting light. Light from the light source enters the viscoelastic lightguide and is transported within the lightguide by total internal reflection. The transported light is extracted from the lightguide and retroreflected at a structured surface of the retroreflective film. The optical device may have a “front lit” or a “back lit” configuration depending on the relative positioning of the lightguide and the retroreflective film. The retroreflective film may include prismatic retroreflective sheeting, holographic film or film structured with diffraction gratings. The optical device may be used, for example, as a sign or marking, a license plate assembly, a tail light assembly for vehicles, a security laminate for protection of documents against tampering, or an illumination device.

主权项

1. An electronic device comprising a keypad, the keypad comprising:
a light source; a viscoelastic lightguide, comprising a pressure sensitive adhesive core, wherein light emitted by the light source enters the pressure sensitive adhesive core and is transported within the core by total internal reflection; and a retroreflective film suitable for retroreflecting light, wherein light being transported within the viscoelastic lightguide is extracted from the lightguide and retroreflected from a structured surface of the retroreflective film.