OLED Displays

Characterisation of displays and luminous surfaces

Displays and luminous surfaces (illuminated signs, backlit keyboards, pictograms, luminous buttons, phosphorescent markings, signage…) possess measurable photometric and colorimetric characteristics.

The ability to characterise these luminous devices by means of adequate equipment allows to objectively quantify their visual performance and verify their regulatory compliance.

PISEO has first-rate skills and equipment to provide you with objective, impartial and quality measurement results for your screens and luminous devices. We are able to provide you with luminance measurements and 2D luminance maps, spectral and colorimetric distribution measurements, as well as flicker measurements, carried out in accordance with international standards.

Luminance and 2D luminance maps

Luminance, which corresponds to the light intensity per unit area expressed in cd / m², is one of the key characteristics of visual experience when looking at a light source.

The higher the luminance and the contrast with the ambient light, the more likely the light source will produce a glare and therefore visual discomfort. This is particularly true with LED lighting devices which produce high levels of luminance (> 5000 cd / m²), especially where LEDs with a very small light emitting surface are directly visible.

In the case of displays (TFT, OLED) and other devices such as backlit keyboards, human-machine interfaces (HMI), pictograms, reflective strips, light buttons, pictograms …, in addition to the point luminance, we will also be interested in average luminance, uniformity of luminance and contrasts over the entire considered light surface.

In this case, the characterisation of the luminance in 2D by means of an imaging photometer will be particularly suitable for effectively and reliably measuring the performance of any light surface.

It allows in particular to carry out all measurements of the performance characteristics of international norms and standards such as IDMS, ISO 9241-305, ISO 3864-4, EN 1838 …

This equipment, which has different objectives and a particularly sophisticated analysis software, allows us to quickly and reliably test your lighting devices and provide you with test reports containing the following characteristics:

  • Spot luminance
  • Average luminance per defined area
  • Uniformity in the area
  • Contrasts between different areas
  • Dead pixels

Measuring equipment

  • Westboro Photonics PF 501 A 5MP photometer, dynamic range from 0.01cd / m² up to 100 Mcd / m²
  • 50mm, wide angle, macro lenses
  • Photometrica processing and analysis software

Spectral distribution and colorimetric measurements

The spectral and colorimetric distribution measurements of displays and luminous surfaces are carried out punctually by means of a spectroradiometer and a remote probe which is applied to the surface to be characterised.

The use of a spectroradiometer allows to measure the entire light spectrum emitted and to calculate extremely precisely the measured colorimetric characteristics (colour point).

Measuring equipment

  • Integrating spheres Instrument Systems 2m and GL Optik 50cm
  • Instrument Systems CAS 120 and 140CT spectroradiometer
  • Flicker measurements on display

The flicker characterises the flickering of displays or any light source. At certain frequencies, it can be seen by the human eye. This phenomenon depends on the electronic design and turns out to be a discriminating characteristic of the quality of the system.

With the appropriate equipment, we offer flicker measures on screens in accordance with international standards IDMS, ISO 9241-305, IEC 62288

Measuring equipment

  • Admesy Asteria Flickermeter