The performance of the fringe projection system, including image quality, nonlinearity of the projected intensity, stability, and switching time for multiple phase-shifted patterns, is essential for fast and accurate shape measurement. A fast and accurate measurement system using a ferroelectric liquid-crystal-on-silicon microdisplay and a high-powered light emitting diode light source is developed. Our results indicate that the nonlinearity of the projected intensity and the stability of the fringe projection were dramatically improved compared with an ordinary commercial liquid crystal display projector. The rapid measurement of the warpage distribution of a flip chip ball grid array electronic package was performed by using the developed system. Nine phase-shifted fringe images with a resolution of 1280 960 pixels were recorded in 1.6 s. In addition, the measurement results obtained by our system agreed well with the results obtained from a micrometer and laser focus sensor. The average error was 2.6 μm, and the standard deviation was less than 10 μm with a 6-mm measurement range. C 2012 Society of Photo-Optical Instrumentation Engineers (SPIE).
- Ferroelectric liquid-crystal-on-silicon microdisplay
- Fringe projection
- Phase-shifting technique
- Shape measurement
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics