| http://www.w3.org/ns/prov#value | - r arranged in the light path of a light beam split by said polarization beam splitter for diverging the split light beam; a concave reflection mirror for converging the light beam from said second lens unit and directing it back to said polarization beam splitter through said second lens unit, said concave reflection mirror meeting a requirement of: 1.5|Pn|<Pr<4.0|Pn| where Pr is a power of
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