Mitsubishi SL2U Service Manual page 52

Defect Criteria
LCD panel White defect
Green None
Red Not more than 1 pixel
Blue Not more than 4 pixels
Blinking pixel
Flaws or foreign objects
Irregular pixels or stains
Discrimination of the pixel defects (white defect, white spot, and negligible white defect)
1. Connect the projector to a PC using the attached RS-232C cable.
2. Load the CD-ROM into the CD drive, and select the CD drive on the PC monitor.
3. Copy the file containing the dot pattern (RGB) from the CD-ROM into the PC.
4. Display the dot pattern of the color to be checked as PC wallpaper. (Select "TILE" in the Display Property setting.)
5. Project the PC wallpaper onto the screen.
6. Check the projected image for any defective pixels.
7. If a defective pixel is found, see the dot near such pixel using a 5 % ND Filter.
8. Compare the brightness of the defective pixel and that of the dot. If the defective pixel is brighter than the dot, such pixel is
judged to be a white defect. If the defective pixel is darker than the dot, go to the next step.
9. Change the 5 % ND Filter used in step 7 with a 2.5 % ND Filter.
10. Compare the brightness of the defective pixel and that of the dot. If the defective pixel is brighter than the dot, such pixel is
judged to be a white spot. If the defective pixel is darker than the dot, go to the next step. (Carry out the next step only with
the green LCD panel.)
11. Change the 2.5 % ND Filter used in step 9 with a 1.5 % ND Filter.
12. Compare the brightness of the defective pixel and that of the dot. If the defective pixel is brighter than the dot, such pixel is
judged to be a negligible white defect.
Negligible
White spot
white defect
Not more than 3 pixels Not more than 15 pixels
Not more than 5 pixels Ignored
Not more than 20 pixels Ignored
: Count a blinking pixel at the time of occurrence as a white defect that the transmittance is
5 % or more. Occurrence of this defect in two adjoining pixels shall be rejected.
: They shall not be seen on the screen when the projected image is in focus.
(The squeezed-out adhesive shall not be seen, either.)
: They shall not cause any trouble in projection.
Dot
Defective pixel
Black defect
Not more than 5 pixels
Not more than 5 pixels
Not more than 5 pixels
ND Filter (1.5 %, 2.5 %, 5 %)
- 16 -
Pixel short cut
(White defects and black defects shall
be counted separately from this defect.)
Not more than 5 pixels
Not more than 5 pixels
Not more than 5 pixels