Corning Incorporated

David August Sniezek Loeber

Daniel Ohen Ricketts

Jacques Gollier

Martin Hai Hu

Dmitri Vladislavovich Kuksenkov

Dragan Pikula

Vikram Bhatia

Xiang-Dong Mi

Nobutoshi Sekiguchi

Backlight units include a light guide plate having a plurality of light extraction features, at least one light source optically coupled to a second major surface of the light guide plate, a rear reflector positioned proximate the second major surface, and a patterned reflective layer positioned proximate a first major surface of the light guide plate. Display and lighting devices comprising such backlight units are further disclosed.

Direct-lit backlight unit with 2D local dimming

Methods of operating a frequency-converted laser source are disclosed. According to particular disclosed embodiments, a laser diode is driven in a pulsed mode to define pixel intensity values corresponding to desired gray scale values of image pixels in an image plane of the laser source. The pixel intensity values are a function of a laser control signal comprising a discontinuous pulse component, a relatively constant intensity component I, and a continuously variable intensity component I*. The pulse width w of the discontinuous pulse component is selected from a set of discrete available pulse widths according to a desired pixel gray scale value. A low-end pulse width w of the set of available pulse widths is established for a range of low-end pixel gray scale values and progressively larger pulse widths w are established for ranges of progressively higher pixel gray scale values. The relatively constant intensity component I makes a relatively insignificant contribution to pixel intensity at the low-end pulse width w for the range of low-end pixel gray scale values and assumes a non-zero value for enhanced conversion efficiency at the progressively larger pulse widths w established for the higher pixel gray scale values. The continuously variable intensity component I* varies according to the desired gray scale value of the selected pixel and the contributions of the relatively constant intensity component I and the pulse width w to pixel intensity.

Pulse mode modulation in frequency converted laser sources

The present invention relates generally to semiconductor lasers and laser projection systems. According to one embodiment of the present invention, a method of correcting output power variations in a semiconductor laser is provided. According to the method, an output power feedback loop is utilized to generate optical intensity feedback signals representing actual output power of the laser source for discrete portions V, V, . . . Vof the image signal. Error signals E, E, . . . Eare generated representing the degree to which actual projected output power varies from a target projected output power for the discrete portions V, V, . . . Vof the image signal. These error signals E, E, . . . Eare utilized to apply corrected control signals G', G&#x2032;, . . . G&#x2032; to the gain section of the semiconductor laser for projection of compatible discrete portions V&#x2032;, V&#x2032;, . . . V&#x2032; of the image signal. According to another embodiment of the present invention, a system is provided for generating a projected laser image.

Correction of power variations in laser sources

Particular embodiments of the present invention relate generally to semiconductor lasers and laser scanning systems and, more particularly, to schemes for controlling semiconductor lasers. According to one embodiment of the present invention, a laser is configured for optical emission of encoded data. At least one parameter of the optical emission is a function of a drive current Iinjected into the gain section of the semiconductor laser and one or more additional drive currents I/V, I/V. Mode selection in the semiconductor laser is altered by perturbing at least one of the additional drive currents I/V, I/Vwith a perturbation signal I/Vto alter mode selection in the semiconductor laser such that a plurality of different emission modes are selected in the semiconductor laser over a target emission period. In this manner, patterned variations in the wavelength or intensity profile of the laser can be disrupted to disguise patterned flaws that would otherwise be readily noticeable in the output of the laser.

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Horseheads, NY, United States of America

David August Sniezek Loeber