MIRROR MOUNT APPLICATION NOTES
High quality metal mirrors,
require mounts that have matching performance and the ability to hold the weight,
prevent warping the mirror, and provide good adjustment range, resolution, and
stability. Metal mirrors are typically heavier than glass mirrors, and are sometimes
not as stiff. Mounts for these mirrors must hold the extra weight without introducing
stresses. Also, metal mirrors are often water-cooled. This requires the mount
to allow for attaching water lines with free, unrestricted movements of both
mirror and water lines without stressing the mirror.
Mount designs using metal
flexures support the heavy weight of these mirrors and provide the necessary
range of motion. A flexure is simply a piece of semi-rigid metal used in a bending
mode. It is a virtually frictionless hinge joint. This approach provides much
greater mechanical and shock stability than relatively fragile bearing loaded
gimbal mounts. Two flexures mounted at right angles to each other allow two-axis
rotation over a range of several degrees, and crosstalk and backlash are virtually
nonexistent. The standard range of motion is 5°. Custom mounts provide up
to 30° range. Simple and reliable threaded push rods, levers and cam arrangements
provide resolutions of 0.01 microns (<0.4 microinch), corresponding to 0.1
microradians, or 0.02 arc seconds, in larger mounts.
Range is the angle that
the mirror is tilted. The incident beam is deflected by twice this angle because
the angle of reflection from a mirror surface is equal to the angle of incidence.
As an example, if the mirror is tilted with respect to the incident beam, by
1°, the reflected beam also has an angle of 1° with respect to the mirror,
and the result is a 2° total deflection of the beam.
The mounts can be used
in vacuum environments or inside laser cavities, and they can also be mounted
in any position. All models are available with custom mounting configurations
for ease of inclusion into the customer’s system designs.
The following table lists
standard mounts, standard resolution, maximum mirror thickness and weight, and
the weight of the mount.
|
TABLE 1
STANDARD MIRROR MOUNTS
Range = 5 "
|
|
MOUNT
|
MIRROR
|
MIRROR
RESOLUTION/5"
|
MIRROR
|
MIRROR
|
MOUNT
|
|
MODEL
|
DIA.
|
Turn ( µ RADIANS)
|
MAX.
THK.
|
MAX.
WT.
|
WEIGHT
|
| MM001 |
1"
|
120
|
0.5"
|
120gm; 4 oz
|
200gm; 7 oz
|
| MM-015 |
1.5"
|
120
|
0.5"
|
280gm; 10 oz
|
370gm; 13 oz
|
| MM-021 |
2"
|
120
|
0.75"
|
680gm; 24 oz
|
566gm; 20 oz
|
| MM-041 |
3"
|
79
|
1.25"
|
2.3kg; 5 lb
|
900gm; 2 lb
|
| MM-061 |
4"
|
130
|
2.0"”
|
7.3kg; 16 lb
|
1.4Kg; 3 lb
|
| MM-081 |
5"
|
100
|
2.0"
|
10kg; 22 lb
|
2.3Kg; 5 lb
|
| MM-101 |
6"
|
81
|
2.0"
|
11kg; 24 lb
|
4.5Kg; 10 lb
|
| MM-121 |
8"
|
40
|
3.0"
|
22kg; 48 lb
|
9Kg; 20 lb
|
| MM-141 |
10"
|
30
|
3.0"
|
70kg; 154 lb
|
16Kg; 35 lb
|
| MM-161 |
12"
|
25
|
4.0"
|
70kg; 154 lb
|
25Kg; 55 lb
|
| MM-201 |
16"
|
15
|
4.0"
|
110kg; 240 lb
|
59Kg; 130 lb
|