Autostereoscopic 3D display characterization is essentially a problem of angular emission. Each point of the surface of the display must emit two or more images that must arrive in the left and right eyes of the observer. A schematic drawing of the device shows immediately that reliable results can obtained only if accurate prediction of the light arriving in each eye of the observer can be made. For a viewing angle measurement made at one location on the display, the requirements in terms of angular resolution Δθ can be calculated easily. The position uncertainty Δx in the plane of the observer at a distance D of the display is given by:

Δx = Dtan Δθ

This uncertainty must be lower than the mean pupil diameter of the human eye (let say 2mm). We see immediately that an angular resolution of 1 to 2° (red arrow) typical of spectrophotometers is unacceptable even for phone cell displays with short working distances. Standard ELDIM EZContrast systems show a resolution of ~0.5° which is not sufficient except for small displays. The system presented hereafter shows a angular resolution more than 10 times better (0.03°) which can cover requirements (green arrow).

High Efficiency

ELDIM manufacture viewing angle instruments based on Fourier optics for more than 10 years. One of their key features is the patented optical configuration which allows controlling the angular aperture of the system independently of the measurement spot size. The very high light collection efficient allows measurement up to very extreme grazing angles (88°) with an excellent accuracy.

High angular resolution

For 3D displays, the priority is made on the angular resolution using dedicated optical design with medium angular aperture (±50°) and large size CCD (16M pixels).

High accuracy

The color accuracy is ensured using 5 dedicated color filters adapted to the spectral response of each CDD. ELDIM is manufacturing itself all the key components of its systems.

High reliability

The quality of the optics is optimum thanks to advance technologies such as magneto-rheological polishing or stitching interferometry. Antireflective coatings and optical alignments are realized in house to reduce straight light and parasitic polarization.

VCMaster3D includes 5 color filters designed specifically for each CCD sensor. The Peltier cooled camera contents a large size 4000x4000 pixels size CCD detector. VCMaster3D includes also different wheels to adjust automatically the measurement spot size (4mm, 2mm, 1mm and 500µm) and the luminance level (flat densities). On VCMaster3DLi the same parameters can be adapted manually using different mechanical cartridges.

VCMaster3D can be provided with dedicated optical bench for easier alignment ad positioning. Manual and automated XY tables are also available to check the geometric correction of the emission at different locations on the 3D displays. FPDLite display driver with specific 3D display features is also available for easy control using any sub-pixel configuration. Completely automated systems with XYZ tables is also available.

Practical angular resolution

Practical angular resolution of VCMaster3D has been measured using a small LED panel. LED are very small bright sources that can be controlled easily. Put in front of a VCMaster3D system at a quite large distance their offer the opportunity to check the practical angular resolution of the system on quasi all the angular aperture.

Results are very near the theoretical values :

VCMaster3D exhibit a resolution better than 0.04°

• EZContrastXL88 gives a resolution of 0.5° in the same experimental conditions