Optical Glass

FOCUSROD -Gradient Index Lens -

  • It is the refractive index profile lens of the radial type which a refractive index gradually decreases to the radial direction from the optical axis center.
  • View angle is wide, and there is a good point that a chromatic aberration is small.
  • It has superior imaging characteristic with a single lens.
  • A shape is a column. Because an end face is flat, it is most suitable as an object lens of a thin endoscope.
  • The refractive index profile is formed by exchanging the silver ion in the glass rod to alkali metals ion.
  • This focus rod does not contain 6 RoHS regulation materials.


Type FR-80 FR-70 FR-65
Diameter 0.350+0/-0.005 0.350+0/-0.010 0.350+0/-0.010
Length of lens 0.732±0.050 0.762±0.050 0.780±0.050
Resolution More 400LP/mm at center More150LP/mm at periphery
Magnification 1:23 1:20 1:18
View angle 80±2° 70±2° 65±2°
Working distance 5.0mm
Field curvature Less 40µm Less 30µm Less 25µm
Chromatic aberration Less 15µm
Central reflex index about 1.674 about 1.665 about 1.660
Convergence parameter about 2.21 about 2.11 about 2.08
  • ※ Filed curvature is a distance of focus at the center of lens and the peripheral .
  • ※ Tolerance of chipping and scratches at the end surface of the lens is outer of 90% of the radius.

Precaution for use

  • Stock in dry conditions
  • Handle the edge of the lens with care, as it chips easily.

Observation case by view angle 80° FOUSROD

Color number

Color number

10 coins

10 coins

Liquid crystal panel

Liquid crystal panel

Observation case by specifications

FR80(View angle80°)Wide view angle type

FR80(View angle80°)
Wide view angle type

FR70(View angle70°)Standard type

FR70(View angle70°)
Standard type

FR65(View angle65°)Low filed curvature type

FR65(View angle65°)
Low filed curvature type

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