A polarized component is obtained with a high conversion efficiency in a
light guide which produces one of the polarized components by having it
transmitted. The light from a light source is incident to a light guide
which comprises a plurality of light guide layers and reflected by the end
surface to an interface between the light guide layers. The polarized
component transmitting through the end surface is rotated in its
polarization plane by a wave length plate and reflected by a reflecting
plate for reentrance to the light guide at the end surface of the light
guide toward the interface. The reentering light mostly transmits through
the interface because the polarization plane is rotated. A reflected light
polarized component is returned to the wave length plate and the
reflecting plate, and directed back to the interface again. The polarized
component transmitting through the interface is similarly transmitted and
reflected in the next interface. The number of interfaces can be reduced
by increasing the reflection of the polarized component reflected in the
interface. For this purpose, the index of refraction in the direction
along the axis of the reflected polarized component is increased by making
the index of refraction of the light guide layer anisotropic.