Acer S5201M Series Service Manual page 74

DMD Image Quality
1. Scope
This document specifies the image quality requirements applicable to the DLP
X and Series 450 Value Component Set. The Component Set provides the DLP
Type X and Series 450 Value Projector with digital imaging functionality based on Digital
Micromirror Device (DMD) technology.
2. Definitions: (Defects and Test Screens)
Blemish
A blemish is an obstruction, reflection, or refraction of light that is visible, but out of
focus in the projected image under specified conditions of inspection (see Table 1). It
is caused by a particle, scratch, or other artifact located in the image illumination path.
2. Dark pixel
A single pixel or mirror that is stuck in the OFF position and visibly darker than the
surrounding pixels.
Bright pixel
A single pixel or mirror that is stuck in the ON position and visibly brighter than the
surrounding pixels.
Unstable pixel
A single pixel or mirror that does not operate in sequence with parameters loaded into
memory. The unstable pixel appears to be flickering asynchronously with the image.
Adjacent pixel
Two or more stuck pixels sharing a common border or common point, also referred to
as a cluster.
Row or Column Defect
The reset boundary artifact is a single row of pixels on the reset group boundaries
that are visibly darker or lighter than the neighboring rows of pixels.
Pond of Mirrors (POM)
POM is a rectangular array of off-state mirrors surrounding the active area.
Eyecatcher
Eyecatcher's are blemishes appearing in the area outside of the Active Area. These
are due to particles and various DMD window or window aperture "defects"
including: digs, voids, and scratches.
Border Artifacts
Border artifacts are a general category of image artifacts that may show up on screen
in the area outside of the active array. Border artifacts include: Exposed Bond Wires,
Exposed Metal 2, and Reflective Edge.
Bond Wires
Bond Wires are the electrical connections between the die and the DMD ceramic
package. If visible, they will appear as short light parallel lines outside of the Pond of
Mirrors (POM).
Exposed Metal 2
Exposed Metal 2 is due to a shift in positioning of either the die or the window
aperture, which may allow light to be reflected off of the layer of metal 2 that is below
the super structure (mirrors). This defect is located outside of the POM.
Reflective Edge
Reflective Edge is light that may reflect from the edge of the DMD window aperture
onto the projection screen. It will appear as a thin diffuse line outside of the POM.
Blue 60 Screen
The Blue 60 screen is used to test for major dark blemishes. All areas of the screen
are colored a Microsoft Paintbrush blue 60 (green and red set at 0, blue set at 60).
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