BenQ SX930 Service Manual Download Page 44

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6. IMAGE QUALITY SPECIFICATION:
1.

Scope

This document specifies the image quality requirements applicable to the DLP

.7XGA Type A and

Series 450 Value Component Set. The Component Set provides the DLP

. 7XGA Type A 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.
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). NOTE: If linear degamma is not
used then the Microsoft Paintbrush values must be adjusted to match the degamma table being used
in order to generate an equivalent blue level on the test screen image.
Gray 10 Screen