Epson Elp-3500, Service Manual, Page: 48 / 114

EPSON ELP-3500 Service Manual
2-19
2.10 R/G/B LIGHT VALVES TO PRISM UNIT
2.10.1 R/G/B LIGHT VALVES
The R/G/B light valves are each high-density, liquid crystal panels of 307,200 pixels
(liquid crystal shutters) of 1.1” (W) x 0.8” (H) (26.9 x 20.2 mm). The condition of the twist
level in the liquid crystal shutter can be controlled in units of 8 degrees from a fully
closed condition (no light transmission) to a fully open condition (no light blocked).
Combining the three light valves (R/G/B) enables projection in full color (approximately
16,700,000 colors). Each light valve has its own part number and is incompatible with the
others. Consequently, their part numbers differ, as summarized in the table below.
Table 2-9.
NAME PART NO. REMARKS
LIGHT VALVE G 1021660 (1028151) *1 Light valve G does not have a position adjust plate.
LIGHT VALVE B 1022063 (1027966) *1 Light valve B has a blue label on the FPC cable.
LIGHT VALVE R 1021674 (1027964) *1 Light valve R has a red label on the FPC cable.
Light Valve B
Light Valve G
Light Valve R
Figure 2-20.
Since the light valves are liquid crystal shutters, they have specific features, depending
on the ambient temperature. At low temperatures, reaction speed is fast. After-image,
light contrast, or thinner color may occur. At high temperatures, reaction speed is
activated. The whole image seems dark.