Caution For Dmd; Focus Stopper Location Verification; Check For Dmd Light Leakage; Caution For Dmd Esd - LG PF1500 Service Manual

(Fig. 4-5-1-2) Resolution Pattern

4.5.2. Focus Stopper Location Verification

(1) Test pattern : White cross-hatch
(2) Mount the lighting assembly to the module inspection jig,
then adjust the focus knob with the resolution measure-
ment pattern (see Fig. 4-5-2-1) and check screen size
conformity. (Wide)
(3) Place the white board 905 mm away from the projection
lens so that the screen size becomes 30 inches wide and
then visually check the focus. (Verify whether the 30"
screen is focused.)
(4) For 120" screen size conformity, adjust the screen in the
same way as 60" and check if "notching marker" is within
the limit line.
- 120" focus OK: "notching marker" is within the limit line.
- 120" focus NG: "notching marker" is outside the limit line.
(Fig. 4-5-2-1) Bushing verification location

4.6. Check for DMD Light Leakage

(1) Go to DMD Check Pattern – Internal Gray Pattern – Full
Gray 30 Pattern and visually check for any light leakage
and then finish checking. (See Fig. 4-6-1)
- DMD valid screen external light leakage configuration:
[The value of (brightness of light leakage / brightness of
the center)] X 100 should be less than 50(%).
- DMD internal screen light leakage configuration: The full
gray 30 pattern should not be seen.
(Fig. 4-6-1) Verification of DMD light source
* Measure the red border with the measurement part of the
CL-200, which is 20 mm (W) x 5 mm (L).
(2) Allow some image inclination on the left side of the screen.

5. Caution for DMD

5.1. Caution for DMD ESD

(1) Connector the grounding to prevent a damage of ESD
(Electrostatic Discharge) when handing the DMD.
(2) Wear a wrist strap to connect the ESD grounding in flesh
necessarily.
(3) Connect the ESD ground to workstation and an electric
conductor.
(4) Save the DMD after getting rid of a static electricity. Keep
it at an exclusive case when moving it When grounding,
open the case.
(5) Put on gloves for preventing static electricity.
(6) All work is done at static free location. Attach the tape or
remove a dust on the DMD front or DMD back pin
5.2. Caution for DMD Clean
(1) Follow the procedure and caution to prevent the screen
from being scratched.
(2) When DMD glass stains with dust, polish the front and
back DMD glass with soft cloth. Then, do it again after
rotating 180 degree the DMD. If necessary, keep under
observation.
(3) Don't clean the DMD with the high pressure. The static
electricity and pressure will damage the DMD.
* Attachment )TI Reference :
DMD Handling Specification, DMD Cleaning
- 8 -
(Digital Micro-mirror Device)