Last Updated：2025/11/19
(optics) A doubly refracting crystal in which the index of refraction for the extraordinary ray is greater than for the ordinary ray, and the former is refracted nearer to the axis than the latter, such as quartz and ice; as opposed to negative crystal: one in which this characteristic is reversed, such as Iceland spar or tourmaline.
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positive crystal
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Source Word
positive crystal
Noun
(optics)
A
doubly
refracting
crystal
in
which
the
index
of
refraction
for
the
extraordinary
ray
is
greater
than
for
the
ordinary
ray,
and
the
former
is
refracted
nearer
to
the
axis
than
the
latter,
such
as
quartz
and
ice;
as
opposed
to
negative
crystal:
one
in
which
this
characteristic
is
reversed,
such
as
Iceland
spar
or
tourmaline.
Japanese Meaning
（光学）二重屈折を示す結晶のうち、異常光線の屈折率が通常光線より大きく、異常光線が軸に近い方向へ屈折するタイプの結晶。例として石英や氷などがある。
Sense（1）
(optics)
A
doubly
refracting
crystal
in
which
the
index
of
refraction
for
the
extraordinary
ray
is
greater
than
for
the
ordinary
ray,
and
the
former
is
refracted
nearer
to
the
axis
than
the
latter,
such
as
quartz
and
ice;
as
opposed
to
negative
crystal:
one
in
which
this
characteristic
is
reversed,
such
as
Iceland
spar
or
tourmaline.
（ plural ）
