Front lighted shadowgraphic method and apparatus

Patent · Tue Feb 26 00:00:00 EST 1985

OSTI ID:5488401

Stone, W J

High contrast silhouette images of a substantially opaque object are obtained using front illumination techniques. The object is frontally illuminated by light of a first polarization. A frontal surface of the object reflects the incident light to an observation station. The polarization of incident light bypassing the object and incident on a background is changed. The background light is reflected to the observation station, and the intensity of one of the two, differently polarized, reflected images is substantially reduced with respect to the other. Apparatus for carrying out the method includes a first polarizer for polarizing frontally incident illuminating light, a second polarizer behind the object and a reflective surface behind the second polarizer. A polarization analyzer, located in front of the object, is used to extinguish one of the two reflected images. Apparatus for carrying out the invention in instruments having a polarized light source and a polarization analyzer includes a combination of a polarizing material, for contacting a rear surface of the object, and a reflective surface provided adjacent the rear surface of the polarizing material. The combination is applied to the rear surface of the object. Back-surface mirrors of pleochroic substrates applied to thin film physical vapor deposited electronic circuit elements enable front lighted shadowgraphic imaging of the elements.

• Assignee: The United States of America as represented by the United States Department of Energy
• Patent Number(s): US 4501473
• OSTI ID: 5488401
• Resource Relation: Patent File Date: Filed date 11 Feb 1982; Other Information: PAT-APPL-347758
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
MEASURING INSTRUMENTS
COMPUTERS
OPTICAL SYSTEMS
PRINTED CIRCUITS
IMAGE PROCESSING
INSPECTION
VAPOR DEPOSITED COATINGS
LENSES
LIGHT SOURCES
POLARIZATION
SHADOW EFFECT
VISIBLE RADIATION
COATINGS
ELECTROMAGNETIC RADIATION
ELECTRONIC CIRCUITS
PROCESSING
RADIATION SOURCES
RADIATIONS
420800* - Engineering- Electronic Circuits & Devices- (-1989)