| F-Theta-Ronar Test Equipment
Just recently, LINOS started offering an option to implement detailed measurements and add protocol data to lenses on serial delivery for the top-quality F-Theta-Ronar lens series.
This measures the spot diameter [µm] at various field positions and the transmission as well as, with a number of lenses, the telecentricity.
The standard test equipment available on the market did not conform to requested performance and operating requirements, which is why LINOS decided to develop their very own equipment.
The technology:
The measurement principle is based on two-dimensional scanning of the point image (aerial image) of the test specimen by means of a spatial sensor.
The ‘infinite’ object location is realised with a diverging, collimated laser beam. The laser source and, if applicable, the divergence unit, is replaced when changing the measuring wave length.
The purpose of the modular structure of the laser source and lens fixture is to enable the flexible and fast set-up for customer-specific measurements and subsequent add-ons.
Transmission:
The transmission is measured by comparing a reference channel parallel with the actual measuring channel. With this measuring method, fluctuations in the intensity of the laser beam have no effect on the measuring result.
An absolute measuring accuracy of < 1% applies when measuring the transmission. This high measuring resolution is required as the detectable effects are already of the same scale.
Point image:
Measurement of the point image comprises evaluation of the FWHM and 1/e˛ point image diameter in two primary focuses with calculation of the azimuth of the principal axes and calculation of the Strehl value.
By measuring the point image for various scan angles and azimuths, it becomes possible to comprehensively characterise the imaging capacity over the image field.
The test equipment is currently undergoing tests for serial production at the company’s site in Regen and is soon to be released for production.
This will make LINOS a leader in measurement and performance documentation in the field of F-Theta-Ronar lenses and thereby offer customers additional security with a quality certification. |
