INTAS 00-061

High-precision low-cost colorimeters and spectrophotometers based on liquid crystalline optics

SUMMARY

Our main target is to develop different kinds of colorimeters and spectrophotometers with a higher accuracy than classical three filter colorimeters (i.e. target accuracy Dx,Dy£0.005) at a lower price than competing systems containing array spectrometers which cost EU 10000 or more. The colorimeters and spectrophotometers will be developed for use in industry like quality control of production of cathode ray tubes (CRTs), light emitting diodes (LEDs) and liquid crystal displays (LCDs). The measuring heads will be hand-held in order to allow measurements at hardly accessible positions. Our further targets are:

• to enable measuring the light of narrowband emitters with a spectral resolution and precision of the dominant wavelength determination of less than 3 nm;
• to fulfil industrial requirements the sensitivity will allow the measurement of displays with a luminance of 1 cd/m2 or light emitting diodes with a luminant intensity of 0.5 mcd. Special measuring optics will be developed for these purposes.
• to provide the dynamic range of the measured light higher than three orders of magnitude;
• to achieve a measuring time less than 1 s when the maximum sensitivity is required.
• The colorimeters will follow the standards published by western organisations like Commission Internationale d'Eclairage (CIE) and the Video Electronics Standards Association (VESA)
• Due to several interchangable optical heads they will in addition be able to measure photometric values (luminance, luminous intensity) together with the color coordinates within one single measurement.

The project is triggered by the increasing requirements to colorimetry and spectrophotometry, e.g. by the invention of bright blue and white LEDs (which will enter the market for lightning technique, and possibly will replace traditional halogen tungsten lamps in many applications) or the increasing use of liquid crystal display. The colorimeters and spectrophotometers today found on the market are either not suited to these applications or are too expensive for use in NIS and often even in European industry. This project wants to fill this gap.

Besides the objectives and expected results stated above the project will lead to the development of new kinds of liquid crystalline optics which can replace classical optics in various applications at lower costs. Some LC optics will provide completely new properties.