Hérouville-Saint-Clair, France
Hérouville-Saint-Clair, France

Time filter

Source Type

Madsen M.H.,DFM A S | Boher P.,ELDIM | Hansen P.-E.,DFM A S | Jorgensen J.F.,Image Metrology A S
Applied Optics | Year: 2016

Fast characterization of 2D gratings is demonstrated using a Fourier lens optical system and a differential optimization algorithm. It is shown that the grating-specific parameters such as the basis vectors and the angle between them, along with the alignment of the sample, such as the rotation of the sample around the x, y, and z axis, can be deduced from a single measurement. More specifically, the lattice vectors and the angle between them have been measured, while the corrections of the alignment parameters are used to improve the quality of the measurement and, hence, reduce the measurement uncertainty. Alignment-free characterization is demonstrated on a 2D hexagonal grating with a period of 700 nm and a checkerboard grating with a pitch of 3000 nm. The method also can be used for automatic alignment and in-line characterization of gratings. © 2016 Optical Society of America.


Boher P.,ELDIM | Leroux T.,ELDIM | Collomb Patton V.,ELDIM | Bignon T.,ELDIM
Journal of Information Display | Year: 2012

In this paper, the problem concerning the color accuracy of imaging systems using color filters is examined. It is shown that the only solution to the problem is to build systems with the spectral response matching the CIE curves as closely as possible. If the spectral response does not closely match the CIE curves, it was demonstrated that calibration cannot solve the problem and will result in very unstable colorimeters. A practical solution that uses telecentric lenses on the sensor side in addition to dedicated color filters for each CCD detector is presented. For systems that closely match the CIE curves, an innovative method of improving the color accuracy based on the precise measurement of the spectral response is presented. The small discrepancies in the spectral response with regard to the CIE curves are corrected in different ways during the measurements. Finally, it is shown that the tristimulus calibration that is used for display measurement is very unstable for systems without CIE matching and is much more stable with systems that closely match the CIE curves. © 2012 Copyright The Korean Information Display Society.


Boher P.,ELDIM | Leroux T.,ELDIM | Collomb Patton V.,ELDIM | Bignon T.,ELDIM
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2011

A method to characterize time sequential stereoscopic 3D displays which is based on the measurement of the temporal behavior of the system versus grey levels is presented. OPTISCOPE SA, especially designed for precise measurement of luminance and temporal behavior of LCD displays is used. The transmittance and response time of the shutter glasses is first evaluated. Then the grey to grey response times of the display alone are measured. Finally, the temporal behavior of the complete system is modeled and grey to grey crosstalks are deduced. Resulting luminance on left and right eyes of the observer are deduced and compared to integrated measurements using a spectrophotometer. Quality control method using grey level test patterns and imaging luminance meter is deduced and applied to different types of commercial 3D TVs. © 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).


Leroux T.,ELDIM
SID Conference Record of the International Display Research Conference | Year: 2011

In this paper, we detail the technical background of our talk and explain the technical details of the Fourier optics technology for viewing angle measurement of displays. The increasing capacities of the ELDIM systems over the years are presented with up-to-date applications. Multispectral polarization measurements for passive glass 3D TVs and ultrahigh angular resolution measurements for auto-stereoscopic 3D displays are also introduced.


Boher P.,ELDIM | Leroux T.,ELDIM | Bignon T.,ELDIM
49th Annual SID Symposium, Seminar, and Exhibition 2011, Display Week 2011 | Year: 2011

Quality control of different shutter glass 3D TVs is realized with an imaging luminance meter. Dedicated pattern is applied to check simultaneously the effect of grey level on both eyes and of temporal synchronization. The grey level instabilities and level of luminance are quantified for fifteen commercial 3D TVs.


Boher P.,ELDIM | Leroux T.,ELDIM | Bignon T.,ELDIM | Collomb-Patton V.,ELDIM
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2010

In this paper we propose a method to characterize polarization based stereoscopic 3D displays using multispectral Fourier optics viewing angle measurements. Full polarization analysis of the light emitted by the display in the full viewing cone is made at 31 wavelengths in the visible range. Vertical modulation of the polarization state is observed and explained by the position of the phase shift filter into the display structure. In addition, strong spectral dependence of the ellipticity and polarization degree is observed. These features come from the strong spectral dependence of the phase shift film and introduce some imperfections (color shifts and reduced contrast). Using the measured transmission properties of the two glasses filters, the resulting luminance across each filter is computed for left and right eye views. Monocular contrast for each eye and binocular contrasts are performed in the observer space, and Qualified Monocular and Binocular Viewing Spaces (QMVS and QBVS) can be deduced in the same way as auto-stereoscopic 3D displays allowing direct comparison of the performances. © 2010 Copyright SPIE - The International Society for Optical Engineering.


Leroux T.,ELDIM | Boher P.,ELDIM
Molecular Crystals and Liquid Crystals | Year: 2014

Optical characterization of all types of displays is mandatory to quantify the different imperfections and compare the different technologies. Standard characterization is focused on luminance and color measurements of the light emitted by the displays. Viewing angle measurements devoted to the angular characterization and homogeneity measurements are the most frequently used. In the present paper we demonstrate that the same type of measurements extended to the polarization analysis of the light emitted by the display can be a powerful tool in order to understand the origin of many imperfections. The present paper is composed of two main parts: first the different measurement tools for viewing angle and imaging characterization are presented and the method used to analyze the polarization state of the light is explained. The second part gives details on some examples of applications for the characterization of display components (brightness enhancement film, backlight), the measurement of the crystal cell rotation inside a standard LCD display, and the characterization of a passive 3D TV. © 2014 Taylor & Francis Group, LLC.


Boher P.,ELDIM | Leroux T.,ELDIM | Bignon T.,ELDIM | Collomb-Patton V.,ELDIM
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2015

OLED displays exhibit luminance fluctuations and color shifts that can be sensitive to human eye in particular conditions. Using viewing angle and imaging multispectral measurements we show that color shifts are generally related to the multilayered structure of each sub-pixel. Interference fringes result in angular variations while thickness variations result in surface non-uniformities. © 2015 SPIE.


Boher P.,ELDIM | Leroux T.,ELDIM | Bignon T.,ELDIM | Collomb-Patton V.,ELDIM
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2012

Two commercial auto-stereoscopic 3D displays are characterized a using Fourier optics viewing angle system and an imaging video-luminance-meter. One display has a fixed emissive configuration and the other adapts its emission to the observer position using head tracking. For a fixed emissive condition, three viewing angle measurements are performed at three positions (center, right and left). Qualified monocular and binocular viewing spaces in front of the display are deduced as well as the best working distance. The imaging system is then positioned at this working distance and crosstalk homogeneity on the entire surface of the display is measured. We show that the crosstalk is generally not optimized on all the surface of the display. Display aspect simulation using viewing angle measurements allows understanding better the origin of those crosstalk variations. Local imperfections like scratches and marks generally increase drastically the crosstalk, demonstrating that cleanliness requirements for this type of display are quite critical. © 2012 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).


Trademark
Eldim | Date: 2013-05-21

Scientific, photographic, optical, measuring, signaling, checking (supervision) apparatus and instruments; apparatus for recording, transmission or reproduction of sound or images.

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