Solid state reflective display

Abstract

A switchable reflective colour filter is provided for use in a display device. The switchable reflective colour filter includes a plurality of sub-pixel regions of at least two colour types, each including a layer of phase change material which is switchable between a first state and a second state, the first and second states being two solid but structurally distinct states having different optical properties. Each sub-pixel region further includes two electrode layers, a mirror layer, and a spacer layer or air gap. The phase change material layer in each sub-pixel region is positioned between the two electrode layers, and separated from the mirror layer by the spacer layer or air gap. The switchable reflective colour filter may be incorporated into a display device including a pixelated switchable absorber. A luminance of coloured light reflected from any of the sub-pixel regions is controllably attenuated by the pixelated switchable absorber.

Description

technical field [0001] The present invention relates to colored reflective display devices, and more particularly to reflective display devices having controllable color capabilities. Background technique [0002] Several types of display devices are well known that are reflective, utilize ambient or artificial light directed towards the front of the display (observer side) as their illumination source, and are capable of color control. These types of displays can be divided into two categories: (1) Displays that generate reflections of arbitrary colors by dividing the reflective area of ​​each pixel into typically three fixed-color reflectances (e.g., red, green, and blue). regions (sub-pixels), and individually modulate the reflectivity of these fixed-color regions in order to produce a combined reflection that can be any superimposed color mixing of colors produced individually by each sub-pixel; Displays with color-tunable pixels for both spectral shape and reflectivity...

AI Technical Summary

Problems solved by technology

This type of area-sharing reflective display has the advantage that only a single active layer is required to control the overall reflectivity, thus low cost and complexity, but has the disadvantage that due to the Limited reflectivity at least some of the visible wavelengths that provide a fixed color, so the overall reflectivity is also limited, typically around 30%

These displays have the advantage that the entire area of ​​a pixel can be used to reflect the desired color, significantly increasing brightness, but have drawbacks of cost, complexity, and in some cases, parallax problems due to stacking multiple layers or Strong change in viewing angle due to cavity path length effects

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