Electronic Autocollimators

ELCOMAT® direct N Product Line

ELCOMAT® direct N Product Line

Product description

Each ELCOMAT® direct N consists of the autocollimation sensor and the software ELCOdirect. ELCOdirect can be used with Microsoft® Windows and a current PC, laptop or notebook. The autocollimation sensor is connected to the computer via the USB interface. A Microsoft® Windows Dynamic Link Library (DLL), autocollimation function, is included with the software ELCOdirect.



The ELCOMAT® direct N is primarily intended for use in optical manufacturing. It is particularly suitable for the following measuring tasks:
  • measurement of small angles
  • high precision angle adjustment and calibration
  • assembly automation
  • wedge and prism angle measurement
  • angular position monitoring
Please also use the technical overview table for all ELCOMAT® instruments to select the most suitable ELCOMAT® N product for your measuring task.


Measuring Principle

The adjacent diagram shows the measuring principle of an ELCOMAT® direct N. First, the image of the reticle is imaged through the lens into infinity (collimated light beam). This means that the light beam is parallel to the optical axis. If the light beam is reflected by a plane mirror with a very high surface quality (< λ/10), the lens images the reticle image on the CCD sensor. The mirror tilt can be determined directly from the deviation of the reflected reticle image from the optical axis of the ELCOMAT® direct N system.


Measuring Range and Distance

The measuring range of each autocollimator remains constant up to a certain distance between the autocollimator and the reflector and then decreases with increasing measuring distance due to vignetting. Since vignetting also affects the measurement uncertainty, we recommend using ELCOMAT direct N autocollimators only up to the maximum measurement distances listed in the technical data or technical overview table for all ELCOMAT devices.


Selection Criteria

You can select the suitable ELCOMAT® direct N from the product line according to the requirements of your measuring task for the measuring range and the measurement uncertainty with the aid of the adjacent illustration.



The main features of the ELCOMAT® direct N product line are:
  • fast and easy measurement of small angles with high accuracy
  • computer-based evalution
  • connection to computer via USB 2.0 interface or higher
  • simple operation
  • cost-effective measuring system
  • easy integration into automated processes
A large selection of different focal lengths allows the selection of the autocollimator suitable for the respective application in terms of measuring range and measurement uncertainty.


Typical Applications

The ELCOMAT® direct N can be used in nearly all applications where electronic autocollimators of the ELCOMAT product line are utilized. Since multiple autocollimation images can be detected and evaluated simultaneously with the ELCOMAT® direct N, it additionally offers some applications like e.g. measurement of wedges or 90°-prism angles. Some of the possible applications are described below:
  • Wedge angle measurement
  • Angle measurement of 90°-prisms
  • Adjustment of optical components
  • Parallelism of two surfaces
  • Position uncertainty
  • Wooble
  • Centering


Wedge Angle Measurement

The wedge angle can be measured either by evaluation via double cross or deflection angle. The first method offers a higher accuracy than the second and does not require additional mirror. A limitation of the method is that it requires a separation of the autocollimation images in the order of the minimum detectable angle difference of the ELCOMAT®. The minimum detectable angular difference of the ELCOMAT® direct N series can be found in the technical data. This results in a lower limit for the measurability of the wedge angle. The second method is not subject to this limitation. It can also be used for wedges with smaller wedge angles.


Angle Measurement of 90°-Prisms

The 90° and 45° error of 90° prisms is measured in two steps. In the first step, the error of the 90° angle is measured. In the second step, the deviation of the 45° angle is determined. Like the wedge error measurement with double cross, this application is based on multiple cross evaluation and is therefore subject to the limitation that this requires a separation of the autocollimation images in the order of the minimum detectable angle difference. These can be taken from the technical data of the ELCOMAT® direct product line. This results in a lower limit for the measurability of the deviation of the 90° and 45° angles.



With the ELCOMAT® direct N product line the alignment of optical components (e.g. prisms and mirrors) is possible. Due to the possibility of simultaneous evaluation of several autocollimation images, components can be adjusted even if autocollimation images of other components appear in the camera image.


Parallelism of Two Surfaces

The ELCOMAT® direct N can be used to measure the parallelism of two or more parallel surfaces. For this an additional plane-parallel mirror is required.



The ELCOMAT® direct N in combination withe centering option of the software ELCOdirect and plane mirror can determine the wobble of spindles and rotary tables.



The ELCOMAT® direct allows the simple and fast measurement of the centering error in reflection and transmission, even during the assembly of a lens system consisting of single lenses (requires the centering option of the ELCOdirect software). For the mounting or cementing of lens systems, we recommend our product CIFOS, which already contains an ELCOMAT® direct system and the associated software is a more versatile and powerful tool.