Tetra-Lateral PSD’s
Position Sensing Detectors (PSD)
Tetra-lateral position sensing detectors are manufactured with one single
resistive layer for both one and two dimensional measurements. They
feature a common anode and two cathodes for one dimensional position
sensing or four cathodes for two dimensional position sensing.
These detectors are best when used in applications that require
measurement over a wide spacial range. They offer high response
uniformity, low dark current, and good position linearity over 64% of the
sensing area.
A reverse bias should be applied to these detectors to achieve optimum
current linearity when large light signals are present. The circuit on the
opposite page represents a typical circuit set up for two dimensional
tetra-lateral PSDs.
For further details as well as the set up for one dimensional PSDs refer to
the “Photodiode Characteristics” section of the catalog. Note that the
maximum recommended incident power density is 10 mW / cm 2.
Furthermore, typical uniformity of response for a 1 mm spot size is ±
5% for SC-25D and SC-50D and ± 2% for all other tetra-lateral devices.
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APPLICATIONS
• Tool Alignment and Control
• Leveling Measurements
• Angular Measurements
• 3 Dimensional Vision
• Position Measuring
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FEATURES
• Single Resistivity Layer
• High Speed Response
• High Dynamic Range
• Very High Resolution
• Spot Size & Shape
Independence
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Great Britain: LASER COMPONENTS (UK) Ltd., Phone: +44 1245 491 499, Fax: +44 1245 491 801, info@lasercomponents.co.uk
