Download presentation
Presentation is loading. Please wait.
1
Interferometer
2
Principle Interferometers are optical instruments used for measuring flatness Determining minute differences in length by direct reference to the wavelength of light.
4
Principle of interferometer
5
Fringes
6
Fringes a b c
7
Fringes A Here the error is indicated by the amount by which the fringes are out of parallelism with those on the base plate B If the work piece is concave or convex, fringe pattern will be as shown in Figure (b). C The surface is flat with slight rounding off at the corner
8
Optical flats Optical flats can be used to measure the flatness
An optical reference flat of known quality A monochromatic light box Solvent and cleaning material
9
Typical setup of optical flat
10
Working
11
Fringe Pattern Air wedges Flatness error of zero
Cylinder with flatness error of two fringes Contact method Convex Cylinder Concave Cylinder Convex Sphere Concave Sphere Convex Spheroid Concave Spheroid Saddle Highly Irregular
12
Air wedge Flatness error of zero (a) (a) (b)
Cylinder with flatness error of two fringes (b)
13
Contact method Convex Cylinder Concave Cylinder
14
Saddle Highly Irregular
15
Interferometer
16
Principle Interferometers are optical instruments used for measuring flatness Determining minute differences in length by direct reference to the wavelength of light.
18
Principle of interferometer
19
Fringes
20
Fringes a b c
21
Fringes A Here the error is indicated by the amount by which the fringes are out of parallelism with those on the base plate B If the work piece is concave or convex, fringe pattern will be as shown in Figure (b). C The surface is flat with slight rounding off at the corner
22
Optical flats Optical flats can be used to measure the flatness
An optical reference flat of known quality A monochromatic light box Solvent and cleaning material
23
Typical setup of optical flat
24
Working
25
Fringe Pattern Air wedges Flatness error of zero
Cylinder with flatness error of two fringes Contact method Convex Cylinder Concave Cylinder Convex Sphere Concave Sphere Convex Spheroid Concave Spheroid Saddle Highly Irregular
26
Air wedge Flatness error of zero (a) (a) (b)
Cylinder with flatness error of two fringes (b)
27
Contact method Convex Cylinder Concave Cylinder
28
Saddle Highly Irregular
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.