Wells Research & Development

Products



Model OS300 - Tabletop Test System

OS300 PixelScope System OS300
OVERVIEW
  • 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.
USED BY
  • 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.
    PRINCILPE 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.

    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.

    FLEXIBILITY

    The OS210B is completely modular, and is compatible with a wide range of OpticStudio™ components.
    LENSES TESTED

    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.

    MEASUREMENTS MADE

    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

    Pupil shape and diameter (F number) as well as Pupli location vs. field angle (pupil aberration) are possible when the included close-focus lens is in place.

    Veiling glare/flare and through focus "star" text are possible with the alternate reticles included with the OS300.

    AUTOMATION

    The standard OS210B is a manual system. However automation modules, including auto-focus, are available as add-on options.
    ACCURACY AND REPEATABILITY

    Unfortunately, MTF measurements have come to be viewed with suspicion by many in the industry, perhaps because of bad experiences with older systems. Wells Research is out to change this: The OS300 provides repeatable, traceable measurements you can have confidence in. Questions you should ask include the following:

    • Are the camera images representative of the lens under test or does the system itself add wavefront error?
      After all, the MTF calculation is just math, and will be accurate to many decimal places. However, the calculated MTF is only as valid as the image captured by the camera. Unless the image reflects the flaws of the lens under test, and only those, flaws, the calculated MTF will be of dubious value. The OS300 optics are diffraction limited, and an inspection certificate is included.
    • Has the operator correctly setup the system?
      In PixelScope, system parameters are entered into graphical pages to minimize the chance of operator error.
    • Is it possible to trace the MTF value to a known standard?
      The OS300 includes a certified “golden lens” for setup and verification, and can save measured images for later review. The OS300 can measure both MTF and 3-bar contrast. In the initial stages of an investigation you may wish to measure both and verify correlation. This provides increased confidence, and is another safeguard against operator setup error.
    COMPUTER AND SOFTWARE

    The OS300 uses our Pixelscope software.