Electronic Autocollimators

Electronic Autocollimators Datasheet

UDT Instruments electronic autocollimators are compact optical instruments designed for measuring the angular position of reference surfaces. They are used wherever flatness, angle, or parallelism must be measured very accurately. Applications include automatic mirror alignment and servo control; quality control and testing of surface plates, machine surfaces and optical components; vibration and stability measurements, and structural flexure measurements.

These autocollimators operate on the same principle as classical models — except that a position-sensing photodiode replaces the human eye. A high-power infrared LED operating at 865 nm (±45 nm) inside the instrument generates a beam of light. It is reflected through a beamsplitter, and then lens-collimated. When this beam reflects off a reference mirror on an object under test, it then travels back through the lens and beamsplitter to the position sensing-detector. Changes in the position of the incident beam on the photodiode are directly proportional to changes in the angle of the reference mirror. The focal length of the lens determines the angle of coverage. An internal blocking filter for visible light less than 780 nm prevents ambient light from interfering with the measurement.

Because UDT Instruments autocollimators use position-sensing detectors in the design, they offer perhaps the widest angular coverage available. Yet, resolutions of 0.2 arc-seconds are common.

Our vacuum-compatible models (V series) are ideal for testing satellite optical systems in a simulated space environment.

All models come with an optical wedge calibrated traceable to the National Institute of Science and Technology (NIST). This wedge permits operators to make simple, accurate calibrations.

UDT Instruments autocollimators are designed exclusively for use with our model 531 display unit. Some autocollimators may also be used with our model 431.

Features

Choice of six models
Vacuum-compatible models available
Wide angular coverage
Resolution to 0.2 arc-seconds