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Incremental Optical Encoders


Optical Encoder - ER6

Optical Encoder System EOI R007

This new Optical Encoder system meets the growing demand for miniaturisation of micro mechanical drives. Additionally the system offers higher precision in controlling motor speed and position.

The light source and photo detector are mounted in the same plane facing the code wheel. The unique design of the code wheel is such that the complete surface of the wheel is reflective. This ensures that nearly all incoming light from the light source, is reflected on the light sensor. This patented feature has resulted in an encoder of compact design, with extremely low power consumption, high resolution and precise output signals. The flexibility of this encoder system allows it to be integrated into a variety of housings of systems and motors with ease.

Code Wheel - Light Source - Light Sensor

Efficient use of light energy

The uniquely shaped reflective surface of the encoder wheel reflects and focuses light emitted by the light source on the light sensor.

More than 90% of light emitted by the light source arrives at the light sensor for signal generation. This allows the implementation of low level light sources, which in turn drastically reduces the power consumption of the entire system. The encoder system is well suited for off-grid systems and mobile devices.

EOI R007 Optical Encoder System


Tolerances between code wheel and sensors have little or no influence on the accuracy of the sensor output signals. This is an advantage over most other comparable systems and improved the reliability of the system as a whole. Extreme environmental conditions have minimal affects on the signal quality. Coupled with the feature of individual design options, easy integration with customer specific products and the miniaturised footprint, this encoder is ideally suited for high reliability applications.

Code Wheel for the EOI R007 Optical Encoder System

Extremely high accuracy

The precision of the code wheel, the focusing of the light beam and the use of a CMOS control circuit achieve a high slew rate and very tight signal tolerances. The specification is based on a code wheel with 128 reflectors and achieves an angular tolerance of less than ± 0.14°. This proves that the design of miniaturised precise angle sensors is both possible and efficient.


Modular system

The accuracy of outputs are highly immune to the positional tolerance between code wheel and sensor. We can provide an encoder as a modular system in kit form. Customers have the option to integrate the sensor and code wheel kit in an existing housing, motor or system. Alternatively customers may integrate the encoder system as a universal encoder in a preferred housing.

Accessories allow customers the capability to adapt the universal encoder to their system.


Optical Encoder Drawing

High Resolution

The unique design of the code wheel enables the Elesta system to achieve higher signal selectivity than comparable reflective systems. This lies in the fact that the light efficiency of the design is a factor two better than most of the comparable systems. The high precision of the output signals allows the system to retain its accuracy after 2-fold and 4-fold interpolation.


Customised solutions

We have the capability to develop customer specific solutions and to adapt the encoder design to meet customer application requirements.



Application Note


      Primary Users

  • Small motor manufacturers
  • Valve manufacturers
  • Pump manufacturers
  • Medical appliance manufacturers
  • Rehabilitation appliance manufacturers
  • Robot manufacturers
  • Remote control manufacturers


      Fields of applicaton

  • Robot technology
  • Printing technology
  • Medical and healthcare appliances
  • Process technology
  • Aerospace & transport
  • Metrology




  • Dose dispensers
  • Actuators
  • Positioning systems
  • Level control systems
  • Rotational speed
  • Angular position & distance measurements
  • Potentiometers


For further information on Optical Encoders contact Willow: +44 (0) 1342 717102


Willow Technologies Ltd. Unit 3 Borers Yard, Borers Arms Road, Copthorne, West Sussex, RH10 3LH, UK

Tel: +44 (0) 1342 717102, Fax: +44 (0) 1342 717014, Email:

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