The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 14, 1995
Filed:
Mar. 23, 1993
Gregory B Demeo, Williamsburg, VA (US);
Lucas Industries, Inc., Reston, VA (US);
Abstract
Disclosed is the backlit display and/or backlit keyboard display which have a controlled level of illumination at the surface thereof. Where such switch and/or display are illuminated by a light emitting diode, the present invention interposes an optical filter between the light emitting diode and the surface of the cover. The optical filter contains a pattern thereon having a variable density distribution of opaque material which in a preferred embodiment is densest in the area closest to the light emitting diode and decreases in density in areas away from the light emitting diode. In a preferred embodiment the optical filter is a 'negative' of the illumination without a filter present. The result in both the switch and display embodiments is a substantially constant level of illumination across the surface of the cover. Further disclosed is at least one slot in translucent layers which may be incorporated in a switch or display which reduces 'crosstalk' between switches and/or displays. Additionally the use of a reflective material as the optical filter, in combination with and separated from a reflective layer near the LED by a separator layer, provides increased illumination of the display or switch.