annular lens soft aperture
环状透镜柔光光圈

• backflush chromatography
• back focal distance
• back focal length
• back focal plane
• back focus
• back focusing
• backgear
• background
• flying spot scannign
• flying spot store
• flying spot television microscope
• flying spot tube
• flying spot tube character generator
• fly-over junction
• fly-past
• fly's eye
• fly's -eye lens
• fly spot scanning
• flywheel
• FM-CW laser ranging
• fm demodulation
• FM laser
• FM reticle
• FM signal
• FM signal generator