Quality control of lenses

The measurement laboratory of Opto-TL is equipped with modern unique devices of our own design - optical benches OS-2000VD (visible range) and OS-2000IK (IR range). These devices control all the necessary parameters of lenses of various complexity. Our company has also created software with the help of which we have reliable results.

Measurements carried out in the visible range and infrared ranges of 3-5 μm (MWIR) and 8-14 μm (LWIR) allow obtaining data on the main quantitative characteristics of the optical quality of lenses: modulation transfer function (MTF), energy concentration function (FCE), focal length, back focal length of the lens, field curvature and distortion.

Optical benches are equipped with mirror collimators with a focal length of 2000 mm, which eliminates any chromatic aberration, except for the chromatic aberration of the measured lens.

With a device specially developed in Opto-TL, you can additionally test lenses for heat athermalization up to + 60 ° C. We also plan to develop an auxiliary lens control device for cooling athermalization down to -60 ° C.

  • Control in the visible range

    Our optical bench OS-2000VD is listed in the State Register of Measuring Instruments and regularly undergoes metrological verification. Its main advantage over the OSK-2 bench, which is the most widespread in Russia, is an extended operating spectral range: from 400 to 900 nm (visible and near-IR), while measurements on the OSK-2 bench are carried out from 400 nm to 700 nm. Tests in a narrower spectral range are carried out using special filters.

    Using a turntable, enhanced by a digital angle indicator, the lens characteristics are measured at different points of the field. The resolution of the angular indicator is 1'40 ”.

  • Infrared control

    The OS-2000IK bench is equipped with two detectors operating in the most frequently used spectral ranges: 3-5 µm (MWIR) and 8-14 µm (LWIR). The use of filters also allows control in narrower spectral ranges.

    Specially developed software for calculating MTF and FCE allows you to obtain objective results due to a verified data interpretation algorithm and attenuation of the possible influence errors such as the error of the matrices on the calculation results. Depending on the selected criterion, control can be carried out with the same reliability with the line, point or edge spread function. The turntable is used to measure the characteristics of the lens at different points of the field.

    We have developed and applied our own original technique for controlling infrared microprojection lenses operating from a finite distance.

    The bench certification procedure has begun with the aim of listing it in the State Register of Measuring Instruments.

  • Climatic tests

    Climatic tests of products at our enterprise are carried out using the TERMOKON TX-60 chamber, which reproduces a wide range of temperatures from -60 to +100 °Ń. The camera allows to set up individual test modes - from a smooth temperature change of arbitrary duration to a thermal shock with a temperature change of +/- 60°C in two hours or even less. In addition to thermal testing of lenses in the chamber, “thermal training” of lenses in mounts can be carried out.

    The chamber is currently undergoing upgrades to incorporate humidity as a test parameter, that will provide a more complete picture of lens performance under different climatic conditions.