Abstract: An optical device comprising: at least one liquid crystal cell comprising liquid crystal material in a cell gap having a dimension at least partly defined by spacers, the liquid crystal cell comprising electrodes for inducing substantially confocal refractive index patterns in substantially concentric, first regions of the liquid crystal material; and within an area bound by an outer edge of an outermost one of the first regions, the spacers being at least disproportionately located in one or more re-set regions between the first regions.

Abstract: An imager is provided. The imager has an imaging platen which presents an imaging surface against which an object to be imaged can be placed. The imaging platen has a photodetector layer and a light guiding layer operable to guide light towards the object. The imager includes a light source operable to emit light into the light guiding layer. The light source is located at an edge of the light guiding layer, to guide light into the light guiding layer of the imaging platen.

Abstract: A method of displaying color data on an electronic paper display is displayed. The method comprises providing an electronic paper display having display pixels at a display pixel pitch and providing a color filter for said display. Said color filter comprises groups of colored filter elements, each said colored filter element having one of a plurality of different colors, wherein each group of colored filter elements defines a pattern of said colored filter elements. In said pattern a colored filter element overlies an integral number, n, of said display pixels, where n is two or more. The method also comprises providing color image data defining a plurality of color image planes, one for each of said different colors. Data in a said color image plane comprises image pixel data defining values for image pixels corresponding to said display pixels.

Abstract: An imager is provided. The imager has an imaging platen which presents an imaging surface against which an object to be imaged can be placed. The imaging platen has a photodetector layer and a light guiding layer operable to guide light towards the object. The imager includes a light source operable to emit light into the light guiding layer. The light source is located at an edge of the light guiding layer, to guide light into the light guiding layer of the imaging platen.

Abstract: The invention relates to an electronic device comprising a limited color display and a method of driving the display. The display has an array of pixels, a driver for driving each of said pixels in said array and a color filter which is aligned with said display whereby each of said pixels is sub-divided into a plurality of sub-pixels of different colors. The method comprises receiving a target image; generating a brightness image for said target image by determining a brightness value for each sub-pixel within said display; generating an output signal from said brightness image by determining an output value for each of said plurality of sub-pixels of different colors within the brightness image; and outputting said output signal to said driver to drive the display.

Abstract: The present invention relates to electronic reading devices, a display driver, a method of driving a display and a method of reducing degradation of a pixel value in a display driven to display a target image. A target image is received, and a pixel influence value for each of the pixels in the target image is determined. A compensation image is generated using the pixel influence value for each of the pixels in the target image, where the compensation image comprising pixel compensation value data for a plurality of pixels in the compensation image, and where the pixel compensation value data representing a colour for a pixel in the compensation image. A display compensation drive signal is then generated using the compensation image and the display driven using the display compensation drive signal to display the compensation image to reduce the degradation in a pixel value.

Abstract: The invention relates to an electronic device comprising a limited colour display and a method of driving the display. The display has an array of pixels, a driver for driving each of said pixels in said array and a colour filter which is aligned with said display whereby each of said pixels is sub-divided into a plurality of sub-pixels of different colours. The method comprises receiving a target image; generating a brightness image for said target image by determining a brightness value for each sub-pixel within said display; generating an output signal from said brightness image by determining an output value for each of said plurality of sub-pixels of different colours within the brightness image; and outputting said output signal to said driver to drive the display.