D-E-F
Dicing
The process of singulating integrated circuits (ICs) from a wafer, or ceramic packages from a larger substrate, by slicing with a circular diamond blade.
Dielectrics
Insulating materials do not conduct direct current (DC) but can be polarized by an electric field, allowing them to store energy in the form of electric displacement.
Diffuser
An optical element that diffuses light from the light source to reduce glare, soften shadows, or produce a more uniform illumination.
FMCW (Frequency Modulated Continuous Wave)
A methodology to measure the distance and velocity of an object by transmitting a continuous wave whose frequency is modulated over time, creating a frequency sweep. The frequency difference between the transmitted and received signals is used to calculate distance (range), while the Doppler shift of the reflected signal is used to calculate velocity.
FPC (Flexible Printed Circuits)
Electronic circuits printed on thin, flexible insulating materials, often used in small electronic devices.
Fine Leak Test
A test to confirm the hermeticity of a package, performed using a helium detector. When testing a package individually, the cavity is inverted on a rubber seal; then, a vacuum pump lowers the pressure inside the package, and helium gas is applied outside the package. If any leak path exists, the helium will be detected, indicating a hermetic failure.
