A new method for quantifying "sparkle" uses a simple measurement which includes a pixelated source, a test sample, and an eye simulator. The degree of sparkle is calculated from the standard deviation of the pixel powers across a portion of the display. Measurements show excellent correlation to human response studies. Author KeywordsSparkle; Display Metrology; Human Response; Perception. Objective and BackgroundDisplay "sparkle" or "dazzle" is a generally undesirable side effect that can occur when introducing antiglare or light scattering surfaces into a flat panel display (FPD) system such as, for example, a liquid crystal display (LCD), an organic light emitting diode (OLED), touch screens, or the like. Sparkle is associated with a very fine grainy appearance of the display. To an observer, this grainy pattern appears to shift with changing viewing angle. This sparkle effect is observed when combining pixelated displays such as that of a LCD with antiglare (AG) or other textured surfaces and differs distinctly in type and origin from the more commonly known "speckle" effect that is observed and characterized in projection or laser systems. The physical origins of sparkle have not been previously well understood, and there has been substantial confusion in the related art between the different types of sparkle or speckle that can be visually observed in projection, laser, or pixelated flat-panel displays. In part due to the lack of basic understanding of the root cause of pixelated FPD sparkle, there have not previously existed any quantitative methods for measuring FPD sparkle that have been shown to correlate well to visual human observations. We demonstrate a system for measuring sparkle which is sensitive to very low levels of sparkle and is linear in response to increasing levels of sparkle. The measurement apparatus consists of an image capture system designed to simulate the response of the human eye. It obtains a high-resolution image of a standardized LCD in which only one color of sub-pixel is illuminated and over which a textured test sample is placed. Within each captured image, a computer algorithm is used to integrate the power within each display pixel and to remove any background light level. The value of sparkle severity is calculated by taking the normalized standard deviation of the pixel powers, which we have termed pixel power deviation (PPD). In this paper, we will discuss the measurement apparatus and image processing algorithm and show the correlation between measured PPD and perceived level of sparkle. ResultsNumerous pixel geometries and pitches are available in today's emissive display technology. The level of sparkle a given textured sample will exhibit is dependent on the pixel geometry and texture to pixel distance of the specific display on which it is used.To provide a quantitative measure of the sparkle inherent to a given textured sample, we choose a single display with square pixels on a 180 μm pitch to use as our emissive source (Lenovo U110 notebook computer display...

We propose and demonstrate a novel implementation of spectral-shearing interferometry (SSI) for reconstructing the electric field of ultrashort pulses by utilizing asymmetric group velocity matching in a long nonlinear crystal. The proposed configuration eliminates the requirement for a linearly chirped auxiliary pulse that is in common in all existing SSI methods, relying on nonlinear conversion to produce a spectral shear.

We use complete spatio-temporal characterization of an ultrashort pulse to study self-phase modulation and other propagation effects in a sample of SF59 optical glass. The goal of this work is to perform accurate experimental measurements of the optical parameters of material samples. From the measured dependence of the self-induced phase shift on the transverse coordinate, we deduce a value of the coefficient n2 of the intensity-dependent refractive index that is in good agreement with previous measurements. We also observe that the spectrum of the transmitted pulse can be explained only approximately in terms of the solution to the nonlinear Schrödinger equation.

In this paper, we describe a series of psychophysical experiments to quantify the relationships between anti‐glare (AG) glass treatments and perceived sparkle in emissive displays. The experiments show the following: (1) that a new measure, pixel power deviation, correlates well with perceived sparkle; (2) that for a given AG treatment, sparkle is worse on high‐pitch displays; (3) that tests of sparkle using small samples provide a conservative bound on perceived sparkle in display‐sized samples; and (3) that sparkle visibility is affected by the content of displayed images. The goal of these efforts is to enable the development of AG glass treatments for emissive displays that effectively reduce front surface reflections while preserving high image quality.