Abstract: A chart recorder or other instrument has a window 10 within which is a key panel 1 composed of materials which are transparent in normal conditions. Incorporated in or associated with the individual elements of the key panel are display elements 22 applied to the transparent window material 20. The display elements are normally transparent but become visible, for example by fluorescence, when illuminated by radiation transmitted through the body of the transparent window material 20, rendering the key panel visible when needed for use.
Type:
Grant
Filed:
November 12, 1993
Date of Patent:
August 6, 1996
Assignee:
Eurotherm Recorders Limited
Inventors:
Peter J. Loeber, Peter W. Hurst, deceased, George R. Hurst, legal representative