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Publication numberUST987003 I4
Publication typeGrant
Application numberUS 05/929,299
Publication dateOct 2, 1979
Filing dateJul 31, 1978
Priority dateJul 31, 1978
Publication number05929299, 929299, US T987003 I4, US T987003I4, US-I4-T987003, UST987003 I4, UST987003I4
InventorsNorbert L. Johnson, Michael J. Knowd
Original AssigneeMinnesota Mining And Manufacturing Company
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Retroluminometer
US T987003 I4
Abstract
a retroluminometer for measuring retroreflectivity of signs or markings at their actual point of use comprises (1) a source of alternating light; (2) optical means for both directing the alternating light onto a sign or marking that is to be tested and for transmitting light retroreflected by the sign or marking onto a panel within the retroluminometer; (3) a matrix of light-transmitting means arranged on the face of the panel; (4) photosensing means optically connected to the light-transmitting means and adjustable to sense and measure the light from different ones of the light-transmitting means, thereby measuring retroreflection at different angles of deviation from the axis of the light beam incident on the sign or marking; and (5) electric circuitry for presenting the photosensed light as a visually-readable measurement. The electric circuitry includes filtering circuitry for filtering out signals having a frequency different from that of the alternating source so as to eliminate the effect of ambient or extraneous light.
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Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US5128804 *Feb 6, 1991Jul 7, 1992Minnesota Mining And Manufacturing CompanyPermeable retroreflective sheeting
US5200262 *Apr 1, 1992Apr 6, 1993Minnesota Mining And Manufacturing CompanyLaunderable retroreflective applique with improved retention of retroreflective elements
US5200851 *Feb 13, 1992Apr 6, 1993Minnesota Mining And Manufacturing CompanyPolymeric matrix opaque to visible light, transmissive to infrared; highway markings
US5207852 *Mar 16, 1992May 4, 1993Minnesota Mining And Manufacturing CompanyMethod for making permeable retroreflective sheeting
US5254390 *Nov 15, 1990Oct 19, 1993Minnesota Mining And Manufacturing CompanyPlano-convex base sheet for retroreflective articles and method for making same
US5338595 *Sep 30, 1992Aug 16, 1994Minnesota Mining And Manufacturing CompanyLaunderable retroreflective applique with metal-azo dye
US5468540 *Jul 29, 1993Nov 21, 1995Minnesota Mining And Manufacturing CompanyRetroreflective article comprising a transparent base sheet and nacreous pigment coating, method for making such a base sheet, and method for making a forming master
US5670096 *Nov 17, 1995Sep 23, 1997Minnesota Mining And Manufacturing CompanyRetroreflective article comprising a transparent base sheet and nacreous pigment coating, method for making such a base sheet, and method for making a forming master
US8016435Apr 12, 2010Sep 13, 20113M Innovative Properties CompanyLamina comprising cube corner elements and retroreflective sheeting
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WO2005047604A1Nov 4, 2004May 26, 20053M Innovative Properties CoRetroreflective elements comprising a bonded resin core and pavement markings
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Classifications
U.S. Classification356/445, 356/447
International ClassificationG01N21/55
Cooperative ClassificationG01N21/55
European ClassificationG01N21/55