Technical Specs

17
SAMSUNG CDT Spec.
Screen and faceplate blemishes
1. Test procedure
Set up the tube and adjust the light output on a blanked raster at the center of the screen for
approximately 54 lm/m² (5 F/L) and 9300° K + 27 M.P.C.D. (OR 6550° K + 7 M.P.C.D.) color
temperature.
The screen should be viewed at a minimum distance of 60cm (2 feet).
Ambient light level at the tube face should be approximately 1.0 lux.
In the non-operating condition the screen may be viewed under highlevel, single source incandescent
light of 700 to 1,000 lux measured at the faceplate surface. The size of a round blemish is equal to its
diameter. The size of an irregularly shaped blemish is equal to its equivalent diameter, defined as the
average of the major and minor axes.
2. Classification of screen and faceplate blemished
Blemishes are divided into phosphor screen blemishes and glass bulb blemishes.
(1) Phosphor screen blemishes
Blemishes are classified depending upon the next table and judged with the standard specified in
clause 4.
Degree of contrast Contents of blemish Valuation of blemish
High-contrast − Black spot
− More than 50% of missing
phosphor dot
The number of blemished
and quality area
Medium-contrast − 25 to 49% of missing
phosphor dot
Ditto
Low-contrast − Non-uniformity lighted part
− Smudge and so on
(2) Faceplate blemishes
Blemishes are classified as scratches and bulb defects and judged with the standard specified in
clause 5.
3. Quality area
Zone
Zone A Zone B
Tube size
Rectangle area concentric
with the center of screen
Remaining useful screen area
19” 315 × 236mm Ditto