Epson RS-353, Service Manual

Page: 46 / 130

2.10 LIGHT R/G/B to PRISM UNIT
LIGHT
The light valve R/G/B each is a high density liquid crystal panel of 307,200 pixels (liquid
crystal shutter) in 26.9
20.2 mm(H). It can control the condition of the twist
level of the liquid crystal shutter in 8 degrees from the fully closed condition (no
transmission of light)
to
the
fully open condition (no shut out of light). Combination of
three light valves (R/G/B) enables to indicate full color colors).
Each light valve which has its own part number is incompatible with others.
Consequently, their part number differs as summarized in the table given below.
NAME PART NO.
I
REMARKS
LIGHT VALVE G 1021660 (1028151) Since the Light Valve G does not have
the po sition ad just plate. to defin e
LIGHT VALVE B 1022063 The Light Valve B has a blue label on
its FPC cable.
LIGHT VALVE RI1021674 (1027964) Light Valve R has a red one.
B
Light valve
Light valve R ’
Figure 20
Since the light valve is a liquid crystal shutter, they have the following specific features
according to ambient temperature.
At low temperature Reaction speed is fast.
Afterimage, light contrast, or thinner color may occur.
At high temperature: Reaction speed is activated.
Whole image seems dark.
2-16