Toshiba TDP-D1, Service Manual

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Appendix C DMD Image Quality
This document is an excerpt from TI’s document 2501907
1. SCOPE
This document specifies the image quality requirements applicable to the DLPTM XGA
ComponentSet. The Component Set provides the DLPTM XGA Projector (herein referred
to as the Projector),with digital imaging functionality based on Digital Micromirror Device
(DMD) technology.. Otherrequirements for the Kit are specified in TI Drawing 4144756.
2. Definitions
2.1 Blemish
A blemish is an obstruction, reflection, or refraction of light that is visible, but out offocus
in the projected image under specified conditions of inspection (see Table 1). Itis caused
by a particle, scratch, or other artifact located in the image illumination path.
2.2 Dark pixel
A single pixel or mirror that is stuck in the OFF position and is visibly darker than
thesurrounding pixels.
2.3 Bright pixel
A single pixel or mirror that is stuck in the ON position and is visibly brighter than
thesurrounding pixels.
2.4 Unstable pixel
A single pixel or mirror that does not operate in sequence with parameters loaded
intomemory. The unstable pixel appears to be flickering asynchronously with the image.
2.5 Adjacent pixel
Two or more stuck pixels sharing a common border or common point, also referred to asa
cluster.
2.6 Streaks
Artifact resulting from localized variation in mirror tilt angle relative to
surroundingmirrors. They are similar in appearance to window scratches but appear at the
mirrorlevel. Streaks appear as faint diagonal or arcing patterns in the image.
2.7 Sea of Mirrors (SOM)
SOM is a rectangular array of off-state mirrors surrounding the active area.
2.8 Eyecatcher
A small localized light “spot” which has high spatial frequency and high
differentialbrightness. These are due to various DMD window or window aperture
“defects”including: digs, voids, particles and scratches.