single refracting surface Flashcards
radius
never changes in a spherical object, even if it is broken into pieces
Where is the optical axis in a spherical object?
(0,0)
Anything that looks to the right
+
Anything that looks to the left
-
What units is radius of curvature in
meters
what units is curvature in?
diopters (inverse of meters)
What relation to curvature and radius of curvature have?
inverse. small radius of curvature has large curvature
A nearly flat surface has…
nearly infinite radius of curvature
Plane surface and curvature/radius of curvature
plane surface has infinite radius of curvature, 0 curvature
What is the origin of ever measurement?
apex
focal point
point where all rays parallel to each other and optical converge at the same point
secondary focal point
point at which the focal point seems to originate from
Optical Power
How strong or weak the system is. The most important thing for optical element. It determines the properties of the optical element.
How are focal point and optical power related?
inversely P=1/f (or n/f if in any medium other than air)
Optical power equation
P=(n’-n)/R n’=2nd medium, n=first medium, R=radius of curvature
What are the units of optical power
diopters
the optical power of a single refracting surface is dependent on
radius of curvature, refractive index of material, refractive index of environment
Concave surface
negative lens, focal point traces before the optical surface
The algebraic sign of the radius of curvature depends on…
the orientation of the vector defining the radius of curvature (right or left)
focal planes
perpendicular to optica axis and the focus
positive (converging) lens focal point
- the principal focus is the point of convergence of a ray bundle parallel to the optical axis
- the secondary focus is the point of origin for rays that when refracted by the lens become parallel
negative (diverging) lens focal point
- the principal focus is the apparent point of origin of an originally parallel beam that when diffracted by the lens becomes divergent
- the secondary focus is the point that the beam appears to converge prior to being diffracted by the lens-while after diffraction emerges parallel to the optical axis
what is the focal point of the eye?
retina
optical power
P=(n2-n1)/R
focal length of a lens
P=1/f
refractive power and focal length of a lens depend on…
- the geometrical shape of the lens (curvature)
- the material refractive index, in relation to the surrounding medium
refractive power and focal length of a lens does NOT depend on…
lens orientation
