The Opticentric is the leading and Most Comprehensive Line of Equipment for Optical Alignment, Centering, Cementing, Bonding and Alignment Turning.
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According to ISO 10110 a centering error is present when the optical and the reference axis of a lens do not coincide, respectively these are different in position or direction. During the process of cementing, alignment and bonding of lenses in a mount, significant centering errors can result and add to the machining errors of a lens. Consequently, the requirements of a high performance optical system can only be fulfilled when all the production steps from the centering tolerance measurement to the assembly of the lens in a mount are planned and designed as an integrated concept.
The TRIOPTICS comprehensive line of equipment under the generic name OptiCentric® has been specifically designed to cover applications related to any type of optical components and to respond to different accuracy degrees.
The OptiCentric System also covers all the production steps from the centration measurement to the alignment, cementing and assembly of optics. The OptiCentric includes valuable tools for any application, from simple and affordable visual instruments to complex, fully automated and PC-controlled production and laboratory stations.
The modular TRIOPTICS product group is able to measure nearly all types of lenses and optical systems from the tiniest and smallest endoscope systems to precision objectives weighting several hundred kilos for wafer steppers in the semiconductors industry.
The products of the OptiCentric range are subdivided into:
• OptiCentric® METRO - for metrology and comprehensive measurement of optical systems.
• OptiCentric® PRO - for production and assembly of objective lenses.
Measurement of Centration Errors of all Kinds of Lenses and Objective Lenses
OptiCentric® METRO instruments are designed to measure centering errors and other parameter of lenses and optical systems. All instruments of the METRO series can be used to carry out measurements using the reflection mode and/or transmission mode, an exception being the OptiCentric® SMART which only works in reflection mode.
OptiCentric® METRO is of modular design, so that the instruments are upgradeable and compatible with each other.
To make the selection of the suitable equipment easier, in a first step the main instrument parts are presented.
1. Autocollimator with CCD-Camera
2. Additional Achromat in X-,Y- adj.Mount
6. Lens rotation device
The OptiCentric® PRO line for production offers a range of fully automated cementing, bonding and alignment turning stations. The powerful products are fully automated and comply in the basic configuration with the OptiCentric® MOT 100. All sub assemblies like a glue dispenser or the motorized stepper are PC controlled.
OptiCentric® Cementing Station
Lens manufacturing not only includes glue bonding of a lens to a barrel, but also the centering and cementing of two lenses to a doublet. For this purpose TRIOPTICS has developed the OptiCentric® Cementing Station as a supplement to the TRIOPTICS OptiCentric System.
It includes a 2-axis x-y piezoelectric fine positioning stage and a lens specific grabber. The grabber does the precise positioning of the upper lens to the optimally centered position with respect to the lower lens.
The centering procedure relies on the proprietary TRIOPTICS MultiLens algorithm. It determines first the optical axis of the lower lens and calculates the target position for the top lens. The top lens is then pushed by the piezo driven grabber to the target position under control of the high resolution CCD autocollimator.
With this technology, doublets with centering accuracies below 1 micron can be achieved. Similar to the Bonding Station, the complete process is computer controlled. Driven by customer demands in the high volume market of plastic molded lenses the process has been optimized for throughput. The complete cementing cycle including UV curing and manual sample handling is performed within less than 10 seconds.
OptiCentric Bonding Station
The TRIOPTICS Automatic Bonding Station extends the capabilities of the OptiCentric System into automatic manufacturing processes of optical components and systems. Modern objective lenses rely more and more on glue bonded components which, besides the lower cost, save space and weight.
The OptiCentric Bonding Station includes all the devices necessary for the precise and automated centering and glue bonding of lenses into barrels and other optical subassemblies. A glue dispenser is mounted on a motorized x-z stepper motor stage for the automatic positioning of the dispenser tip to the gluing position.
The dispensing process is computer controlled and the glue can be dispensed continuously or segmented around the lens. A second x-z stepper motor stage moves a precision piezoelectric manipulator to the edge of the lens to be centered. The piezo manipulator allows for a fine positioning of the sample lens with submicron step resolution and accuracy.
The centering process is controlled by the OptiCentric System which relies on a high resolution CCD autocollimator and the precise sample rotation with an air bearing.
High-precision centering results better than 2.5 microns are typically achieved in 2 min processing time including UV curing time. The UV curing of the glue after lens alignment is enabled by a computer controlled UV light source and several light guide outlets.
The complete bonding process is controlled by an integrated software program for all functions. A simple script language allows the flexible programming of the bonding process.
The complete manufacturing cycle can be programmed with an easy teach-in procedure using the manual stage controls. Of course, different procedures for varying sample types can be saved in files for later use.
OptiCentric® Alignment Turning
In al ignment turning, opt ical uni ts are processed by mechanical machining. The holder with the lens is first placed into a clamp, and the centering error measured.
The clamp is then aligned in such a way that the optical axis and rotational axis coincide. The holder is then lathed away in a second process step.
The most important components in this fabrication process are the centering lathe with a high-precision axis, the OptiCentric® Alignment Turning System for precise measurement of the centering error, and the mechanically adjustable clamp. The axis of rotation ensures that the fabrication process is carried out stably and precisely. It is mounted on hydrostatic bearings and its radial deviation is less than 0.08 μm.
The OptiCentric® Alignment Turning System determines the orientation of the optical axis of the workpiece relative to the axis of rotation. The system is available in variants with one or two electronic autocollimators. If two autocollimators are used, both centers of curvature of the lens can be measured at the same time. With only a single autocollimator, two measurements are taken one after the other, and the position of the optical axis is determined using the MultiLens® algorithm.
The sample is then translated and tilted in the X and Y directions using the adjustment clamp in such a way that the optical axis of the sample coincides with the axis of rotation.
Accuracy in the submillimeter range can be achieved in this way. The mechanical interlock on the adjustment clamp ensures that the position of the optical axis relative to the axis of rotation does not change while the holder is centered to the rated diameter. In addition, both flange surfaces of the holder are also machined.
An optical sensor that measures the distance between the flange surface and the vertex of the optical surface of the workpiece can optionally be used.
The specification of the alignment turning station is:
Centering accuracy: < 0.1 arcmin (tilt)
< 2 μm (decenter)
Machining tolerances: < 2 μm
Flatness of plano surfaces:< 1 μm
Cylindricity of lens cell: < 1 μm.