NEC MultiSync FP1350 Service Manual page 110

[B] Defective AR-film standards
1. Test conditions
1) Place the bulb on the test table and light it with the white fluorescent lamp from the above.
2) Illuminance on the surface of the bulb tube shall be more than 1000 Lx, less than 1500 Lx.
3) Observe at a 40cm distance from tube surface, ignore the defects that can not be seen at this distance.
2. Zone classification
Zone A: Internal rectangular area with the horizontal and vertical dimensions shown in the following fig. In
which the screen center is located in the middle.
Zone B: Area between the edge of Zone A and phosphor screen.
Zone C: Area outside the edge of phosphor screen.
y
Dimension table
Size
41cm
46cm
51cm
3. Defect standards
3-1. Scratch (Glass and coating)
Width
More than 0.16mm
0.11 ~ 0.15mm
0.06 ~ 0.10mm
Less than 0.05mm
(Note 1) In the case that it has very law contrast, regard it as a stain, not as a scratch and apply the ratings in the
3-2. even if the scratch7s width is in excess of 0.16mm.
(Note 2) There is no specified standards regarding Z one C. However, no defect is acceptable that damages the
quality of the product. Discuss regarding the limitation, if necessary.
3-2. Opacity such as stain, etc. and peeling of coating
Defect contrast shall be classified. And judge defects in each contrast classification, according to size.
Definition of contrast
• High contrast: foreign object that blocks off the light from the phosphor screen, such as graphite
and dust, etc.
• Middle contrast: Translucent foreign object and stain (Ex. Solidified coating materials and white
stains, etc.)
zone A
x
Unit = mm
X
300
360
395
Zone A + B
Not acceptable
Length within 13mm
Length within 26mm
No limitation of length
Edge of phosphor screen
zone B
zone C
Y
225
270
295
6-6