Radiant energy – Photocells; circuits and apparatus – Optical or pre-photocell system
Patent
1976-09-24
1978-06-27
Nelms, David C.
Radiant energy
Photocells; circuits and apparatus
Optical or pre-photocell system
356211, G01N 2130
Patent
active
040977510
ABSTRACT:
An instrument for measuring the retroreflectance properties of surfaces to angles including an angle of zero degrees of the incident beam. The instrument comprises a source of collimated radiation, a beam splitter such as a cube biprism, a beam chopper, a radiation sensor system operated in a coherent detection mode with the chopper, and indicating and/or recording means. A beam of radiation aimed at a normal incidence at the surface of the test specimen is passed through the biprism which has its 45.degree. diagonal semi-reflecting surface interposed in the beam. The undesirable part of the beam is reflected off the diagonal surface to and through one of the sides of the biprism and the reflection back therefrom passes through the diagonal surface and then travels to the radiation sensor. The desirable part of the beam from the radiation source goes directly through the diagonal surface and passes to the surface of the specimen. Radiation incident on the specimen surface is reflected back to the biprism whence it is partially reflected off the diagonal surface and it too passes to the sensor. The chopper is interposed in the radiation path between the biprism and the specimen and periodically interrupts the radiation therebetween. The sensor is operated in a coherent-detection background-discrimination mode with the chopper such that a signal indicating the retroreflectance properties of the specimen surface is obtained.
REFERENCES:
patent: 3606541 (1971-09-01), Sugano et al.
patent: 3804532 (1974-04-01), Patten et al.
patent: 3836787 (1974-09-01), Ash
patent: 3892494 (1975-07-01), Baker et al.
patent: 3904293 (1975-09-01), Gee
patent: 3977789 (1976-08-01), Hunter et al.
Egan Walter G.
Hallock Herbert B.
Hilgeman Theodore W.
Gill Mellor A.
Grumman Aerospace Corporation
Nelms David C.
Sunderdick Vincent J.
LandOfFree
Retroreflectance measuring apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Retroreflectance measuring apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Retroreflectance measuring apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2306572