optical flat


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optical flat

[′äp·tə·kəl ′flat]
(optics)
A disk of high-grade quartz glass approximately 2 centimeters thick, with a deviation in flatness usually not exceeding 0.05 micrometer all over, and a surface quality of 5 microfinish or less; used in determinations of surface contour and in comparison of lineal measurement.
A plane surface, with deviations from a plane surface generally not exceeding one-tenth of a wavelength of light, used to redirect light in a telescope or other optical instrument.
References in periodicals archive ?
The coated optical flat photoresist is then delivered to the pre-curing station.
"I've already completed the perforated 8-inch optical flat and long-focus 6-inch primary for a Russell W.
Used to apply thin layers of coatings to increase or decrease the optical transmission on a lens or optical flat, the SPECTOR-HT is equipped with a powerful ion source, a high-voltage extraction system and a large substrate holder.
Their material can be polished to the mirror finish of a quartz optical flat, and has the optical reflectivity needed for interferometric calibration measurements.
The upper section is a detachable spar made from a 33-inch length of heavy-walled 1-inch-diameter steel tubing that connects the 3-inch-diameter tube to the housing of the optical flat. Short lengths of precision-ground stainless-steel shafting pressed into the ends of the spar slide into mating sleeves located on the undersides of the 3-inch-diameter tube and the housing of the optical flat, where they are retained by knurled thumbscrews that bear against milled flat surfaces.
Tenders are invited for Works contract for calibration of primary masters (static torque meter, angular gauge scale, optical flat and angle gauge block) at bhel trichy for 2018-19.
Tenders Are Invited For Works Contract For Calibration Of Primary Masters (Static Torque Meter, Angular Gauge Scale Optical Flat And Angle Gauge Block) At Bhel Trichy For 2018-19.
Quotation are invited for Supply and installation of Calibration Equipments with Traceable Calibration Certificates & accessories at LARPM, CIPET-Bhubaneswar- Optical Flat Qty- 01 set, Inside Micrometer Checker/Calibrators Qty- 01Pc,High Accuracy micrometer Qty- 01Pc,etc
Tenders are invited for Optical Flat To Check The Flatness Of External Micrometer.
I already had a 4 1/4-inch optical flat for reflecting starlight upward to the refractor's objective.
The drive and optical flat are protected from the elements by a 4-by-6-foot weather-stripped cover.
Surface [R.sub.5] need not be extremely flat; it can show up to about 30 interference fringes when placed in contact with an optical flat, but these fringes should be fairly circular (within one or two fringe spacings).