What is the OS300?

• The OS300 is an automated test station, intended for the evaluation of small lenses with EFL between 1 and 10 mm.
  
• The OS300 may be used for in-depth analysis of engineering samples. In a minute or so it is possible to collect through-focus data at up to 10 field angles and 8 azimuth locations, a task which would would require 80 telescopes on competing equipment.
  
• When a simple go/no go decision is needed, the OS300 can collect data at 9 total field locations in under 10 seconds.

Who would use an OS300?

Manufacturers of small lenses use the OS300 to

• Provide in-depth evaluation data for potential customers.
• Perform periodic sampling for trend analysis.
• Perform 100% inspection in situations where a multi-telescope production tester is not available.

Users of small lenses use the OS300 to

• Perform in-depth evaluation of lenses from multiple manufacturers.
• Perform periodic sampling for trend analysis.

What kind of lenses can the OS300 test?

The OS300 is intended for testing small lenses of the type used in cell-phone cameras, personal digital cameras, endoscopes, etc.

The OS300 is most useful for lenses in this range:

• EFL from 1-10 mm
• F-number from 0.5 to 20
• Aperture from 0.5 mm to 5 mm
• Field of view up to +/- 90 degrees

The OS300 is generally used to test lenses at infinity. In some situations the OS300 can be used for testing endoscope lenses at finite conjugates.

Principle of operation

• Lenses are tested "in projection". A back-lit reticle is placed at the focal plane of the lens under test, and a precision telescope is used to capture the image.
  


• The OS300 uses a single telescope, which pivots around the pupil of the lens.
  
  Competing machines use multiple telescopes, generally set up to test the lens at 5 or 9 locations in the image plane. The multiple telescope configuration allows faster test times, but it limits testing to 5 or 9 locations in the image.


• The OS300 has three motorized motions:
  • The reticle is mounted on a motorized Z stage. This allows initial autofocus, as well as collection of through-focus data.
  • The telescope pivots around the pupil of the lens. The maximum pivot angle is a full 90 degrees.
  • The lens chuck rotates around the optical axis.


• As a result, the OS300 can measure the lens at any location in the image plane.

What measurements can the OS300 make?

The OS300 can directly measure:

• MTF at any location in the image, presented as a conventional MTF plot, or as measured values at discrete spatial frequencies (eg 0, 10, 20.. lines/mm)
• MTF vs field angle
• MTF vs focus
• EFL
• BFL
• Field flatness (curvature, tip)
• Distortion
• Vignetting / relative illumination
• Chief ray angle
• Centration

The following measurements are possible when the included close-focus lens is in place:

• Pupil shape and diameter (F number)
• Pupil location vs. field angle (pupil aberration)

The following measurements are possible with alternate reticles which are included with the OS300:

• Veiling glare / flare
• Through focus "star" test

What software is used?

The OS300 uses a new version of our easy-to-use program "PixelScope". You may download an evaluation copy of PixelScope-OS300 software from the WRD website.

Can I have some sample lenses tested?

• We would welcome a visit so you can try out the OS300 in person. Our facility is in Lincoln Massachusetts, about 10 miles outside Boston.
• If you would prefer, you can mail us lenses, and we will send you a test report.
• To discuss either of these options further, please call us at 781-259-8667.