FPD Light Analyzer, OL0011

The FPD Light Analyzer OL0011 (FPD = Flat Panel Display) has been developed for measuring luminance and color on all types of flat screens and panel lights. A standard USB connection is used for both communication and voltage supply with the instrument logged in to the system as a USB HID device. The corresponding drivers for this device class are available as an integral part of all current operating systems.

The elaborate integrated aperture lens with an aperture angle of only +/-1.8° not only enables normal contact measurements but also tele-measurements at larger distances.

Due to the use of an XYZ sensor, the measuring results are optimally pre-processed in the front end in a standard-compliant way. The associated filters form an integral part of this sensor element and are based on long-term stable interference filters (the energy filtered out is not converted into heat, but reflected).

The special optics integrated enable use of the measuring instrument in a very wide range of industries. Among them also everyday-use flat screens such as computer monitors, cell phones, tablet computers and televisions. Measurements can also be performed on beamers and similar projection systems, digital signage products and, last but not least, electronic traffic and direction signposting systems as well as warning and alarm systems.

Especially with large outdoor signage, e.g. used as road signs or outdoor advertising, being able to perform measurements on site without having to take down the units or causing considerable downtime would be helpful. To enable this, the measuring instrument offers a very wide dynamic range in combination with high 16-bit resolution. In this way, a large display can be measured from a great distance even under normal daylight conditions, using additional software-controlled equipment.

Given this wide variety of applications, the question is whether measurements on different types of light sources, or even light sources unknown at this time, would produce significant measuring errors.

The answer is no, because the achievable accuracies are comparable to the results obtained using sophisticated spectrometers! For this purpose, the instrument allows up to 256 different user calibrations to be stored at the same time that can be freely selected for a measurement.

A user calibration can be generated independently for color measurement and luminance measurement. As the name ‘user calibration’ already implies, the end user can perform these calibrations himself as needed. As a result, the unavoidable deviations of real filter functions of the sensor element in the front end can be adapted to a specific light source technology.

The problem of the deviations in the filter functions from the CIE1931 standard and the partly extreme mismatch to specific types of light sources resulting, applies to all filter-based instruments available on the market from any supplier. Partly, these instruments are only ‘calibrated’ for specific monitor types, and whilst it is possible to reload available correction factors, these will apply to a whole series of devices without addressing ‘type-specific issues’. Only very few instruments can be adapted to new technologies at all. On the FPD Light Analyzer OL0011, the calibration is performed for an individual device – and as the name implies – the user is able to perform the calibration himself at any time! OPTO4L supports this process with the corresponding tools and comprehensive documentation. As a result, the user obtains a calibration producing levels of accuracy for a specific light source technology usually only achievable using sophisticated spectrometers.

Speaking of spectrometers – have you ever performed measurements of a dark shade of gray on a high-quality monitor for medical applications using a spectrometer-based system? Then you will know that measuring times of 60 seconds or more are nothing unusual! For these measurements, the advantages offered by filter-based systems like the OL0011 become apparent – the longest individual measurement without averaging only takes 1 second to perform. This enables additional averaging within a range of 4–8 cycles depending on the actual requirements of the application, allowing to measure even very dark colors through to black in well under 10 seconds.