Module 7 Flashcards
These are optical media with
two plane and well-polished
surfaces which are inclined
towards each other.
PRISMS
are blocks of optical
material with flat polished sides
arranged at precisely controlled
angles to each other, which
deflect, deviate and rotate beams
of light as well as dispersing their
wavelengths.
PRISMS
A ray of light after passing through
a prism is bent towards the
base
The image of an object seen through
a prism is displaced towards the
direction of the
apex
- Image transposition
- Deviation
- Displacement
- Dispersion
FUNCTIONAL
PROPERTIES
Apical angle is 15 degrees or less
THIN PRISMS
or
OPHTHALMIC PRISMS
The angle formed by the emergent
ray with the original path of the
incident ray.
DEVIATING ANGLE
A prism with a power of One Prism
Diopter can displace a ray of light by
1cm for every meter distance that
the light travels.
PRISM DIOPTER
A prism with a power of One
Centrad produces a displacement of light
by 1 cm for every meter distance that
the light travels on the circumference of
a circle.
CENTRAD
is an angle subtended at
the center of a circle by a length of arc
equal to the radius of the circle.
Radian
A prism with a power of One Prism
Degree can displace a ray of light by
0.9 cm for every meter distance that
the light travels.
PRISM DEGREE
A prism with a power of One Prism
Degree Deviation can displace a ray of
light by 1.75 cm for every meter
distance that the light travels.
PRISM DEGREE DEVIATION
These are the plane, smooth and well-polished surfaces of a prism which are inclined towards each other.
Refracting Surfaces
the surface where incident rays first hits the prism
1st Refracting Surface
the surface where light rays emerge or leave the prism.
2nd Refracting Surface
