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6. CRT Limits of Screen and Faceplate Blemish
6.1 CRT Face plate defect
6.1.1 Inspection condition
1) Adjust each gun to provide approximately 34cd/m2 of 9300K+27M.P.C.D. (or 6550K+727M.P.C.D.) light at
the center of the screen. Ambient light level at the tube face should be approximately 10 luxes.
2) When the tube is not operating, the screen should be viewed under high-level source incandescent light of
approximately 200 luxes measured at he faceplate surface.
3) The screen should be viewed distance of 60 cm for both cases.
4) View white and R, G, B individual color, and faceplate appearances.
6.1.2 Quality zone
The screen quality area is divided into the following two quality zones.
Zone A : Inside of the central rectangle of horizontal 360mm by vertical 270mm on the screen.
Zone B : Outside of this rectangle on the screen.
6.1.3 Screen and Faceplate Blemish Acceptance Criteria
1) Screen blemish
a. Minimum separation of defects : d
b. Average diameter of defects :
Turn of (a + b) / 2
c. Acceptance criteria for screen blemishes
Black spot, missing aperture
Average diameter (mm)
0.51 ~
0.31 ~ 0.50
0.15 ~ 0.30
Discoloration, stain, Missing phosphor, etc.
Average diameter (mm)
0.51 ~ 0.75
00.15 ~ 0.50
Note 1: Applied for each color independently.
(a: length, b: width)
A
0
0
6 (note 1)
A
0
2
B
A + B
0
0
0
0
6 (note 1)
10 (note 1)
B
A + B
1
-
3
-
5-26
d
a
b
Minimum distance
-
-
10mm
Minimum distance
20mm
20mm
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