Everything You Need to Know About TV Technologies

DLP rear-projection

Newer technologies like DLP, LCD and LCoS have brought rear-projection from the dark ages of the cathode ray tube. DLP stands for digital light processing. As with the older CRT rear-projection, a mirror is the key to its functioning.  Or, rather, mirrors: 1.3 million of microscopic mirrors, each corresponding to one pixel in an image. They are placed on the surface of a chip called DMD (digital micromirror device) and each one is about 1/5 the width of a human strand of hair. A lamp light source beams through a colored spinning wheel and hits the chip. The tiny mirrors tilt and rotate stimulated by several electrostatic discharges and reflect the colored beam of light unto the screen. The DMD chip can display high-definition images (720 or 1080 pixels) with 16.7 million colors.

Model example: Mitsubishi WD-65733 (65" 1080p HDTV)

Strong points

• Excellent black level and contrast ratio
• Greater viewing angles than those of CRT rear-projectors
• No burn-in such happens with plasma
• Less bulky set than those of CRT rear-projectors.

Weak points

• Chip substitution can be expensive
• “Rainbow effect”: some sensitive eyes notice the rapid changing of color spectrum (red, green, blue) caused by spinning wheel between the lamp source and the DMD chip.