Johan Bergquist

49.2: Field-Sequential-Colour Display with Adaptive Gamut

minimum necessary gamut is calculated frame-by-frame and the primaries are desaturated dynamically by simultaneously turning on several backlight colours during each primary field. Depending on the display response, this leads to better backlight utilization, increased luminance, and/or enhanced moving image quality. For a fast-response, three-primary field-sequential-colour display, the luminance can be increased by up to 300% for unsaturated content. 1. Introduction display power of a mobile phone is typically 20-30% of the total system power so stand-by and transflective modes, automatic backlight dimming, and screen saving are frequently used. On the other hand, high-bandwidth wireless infrastructures, digital TV broadcasting, and miniaturised gigabyte local storage will enable ubiquitous multimedia consumption on mobile devices, which require continuous and full display operation. This together with a moderate progress in battery technology and escalating CPU performance requirements will drain the battery unacceptably fast. At the same time, requirements on colour gamut, outdoor contrast, and moving image quality are higher than for traditional mobile applications. The objective of this work is to explore ways of lowering display backlight power consumption and maximise image quality in a highly dynamic fashion by adapting the display driving to the image content and luminous environment.

The effect of stereoscopic viewing in a word-search task with a layered background

— The benefits of stereoscopic viewing were explored in searching in words superimposed over a background. In the first experiment, eight participants searched for text in a normal 2-D display, a 3-D display using a parallax barrier, and a darkened 2-D display of equivalent brightness to the 3-D display. Word-search performance was significantly faster for the bright 2-D display vs. the 3-D display, but when brightness was controlled, performance on the 3-D display was better relative to the 2-D (dim) display. In a second experiment, the effect of floating text vs. sinking background disparity was assessed across four background conditions. Twenty participants saw only the floating-text (FT) condition and 20 participants saw only the sinking-background (SB) condition. Performance of the SB group was significantly better than that of FT group, and the advantage of SB disparity was greater with the more-complex backgrounds. Thus, when a parallax-barrier 3-D display is used to view text or other figural information overlaid on a background, it is proposed that the layer of primary interest (foreground) should be displayed with zero disparity (on the physical display surface) with the secondary layer (background) appearing to be sunk beneath that surface.

A novel diffractive backlight concept for mobile displays

efficiency demands on mobile communication device displays have become severe with the emergence of full video capable phones and mobile telephony services such as the third- generation networks (3G). One way of reducing the power dissipation of a mobile liquid-crystal display (LCD) is to efficiently distribute and outcouple the light available in the backlight unit (BLU) to direct the light in a spectrum-specific fashion through the respective color pixels. This paper describes a diffractive optics approach to realize a novel backlight unit. A model grating structure was fabricated and the outcoupled distribution of light was studied. The results verify that the new BLU concept based on an array of spectrum-specific gratings is possible.

52.2: Display with Arbitrary Primary Spectra

Individual differences in colour sensation of a single display (observer metamerism) can be reduced by synthesizing and adapting the primary spectra to the physiological spectral response of the observer. The technique can also be used to synthesize the eigenspectra in multispectral imaging, and thereby provide an alternative to multi-primary displays.

5-2: A Novel Diffractive Backlight Concept for Mobile Displays

Power efficiency demands on mobile communication device displays have become severe with the emergence of full video capable phones and mobile telephony services such as the third-generation networks (3G). One way of reducing the power dissipation of a mobile liquid-crystal display (LCD) is to efficiently distribute and outcouple the light available in the backlight unit (BLU) to direct the light in a spectrum-specific fashion through the respective color pixels. This paper describes a diffractive optics approach to realize a novel backlight unit. A model grating structure was fabricated and the outcoupled distribution of light was studied. The results verify that the new BLU concept based on an array of spectrum-specific gratings is possible.