CONEX-PSD
Two-Axis Position & Power Sensing Device
3.0
Functional Description
3.1
Principle
Position Sensing Devices (PSDs) consist of a p-n junction photodiode in which
two sides of the junction have electrically separate contacts.
X, Y positions returned by the Get Position GP command are given according to the
above referential.
3.2
Sensors Outputs
For Si sensor, the cut-off frequency is at 319 Hz.
For Ge sensor, the cut-off frequency is at 136 Hz..
3.3
Beam Size Considerations
3.3.1
Max. Size
For best measurement quality, the beam should remain within the sensitive area (9 x 9
mm for Si, 10 x 10mm for Ge). If the beam is moving during measurement (
∆
X,
∆
Y),
its size should be reduced using the following formula:
Maximum Beam size for Si: BS
x
= 9 mm –
∆
X and BS
Y
= 9 mm –
∆
Y
Maximum Beam size for Ge: BS
x
= 10 mm –
∆
X and BS
Y
= 10 mm –
∆
Y
3.3.2
Min. Size
To maintain measurements quality, it is recommended to use a beam size
≥
0.2mm
WARNING
M
INIMUM BEAM SIZE
: 0.2 mm.
7
EDH0315En1030 — 07/16
