{"id":2742,"date":"2026-03-06T16:32:56","date_gmt":"2026-03-06T08:32:56","guid":{"rendered":"https:\/\/iris-opt.com\/?p=2742"},"modified":"2026-03-29T00:16:19","modified_gmt":"2026-03-28T16:16:19","slug":"epaper-color-gamut","status":"publish","type":"post","link":"https:\/\/iris-opt.com\/en\/blog\/epaper-color-gamut\/","title":{"rendered":"The Secrets to e-Paper Color Gamut"},"content":{"rendered":"

Excerpted from a contribution by Professor Hung-Shing Chen, Graduate Institute of Electro-Optical Engineering, National Taiwan University of Science and Technology, to Science Monthly, March 2026<\/em><\/p>\n\n\n\n

E-paper (electronic paper) is currently the display technology that most closely replicates the appearance of real paper, while also offering the dual advantages of being eye-friendly and energy-efficient. The two most promising color e-paper technologies are microcup electrophoretic ink (developed by E Ink) and Cholesteric Liquid Crystal Display (ChLCD). How do these two technologies differ in reproducing color? And which type of e-paper comes closer to the color quality of printed materials?<\/p>\n\n\n\n

E-paper: a clever fusion of printing and displays<\/strong><\/h2>\n\n\n\n

E-paper is the display technology that most closely approximates the look and feel of real paper. It offers two major advantages: eye protection and energy savings, along with the potential for flexibility and a paper-like display experience. Its display principle resembles that of conventional printed materials \u2014 light from an external source reflects off the display surface and enters the viewer\u2019s eyes, rather than being emitted directly. Compared with traditional self-luminous displays, e-paper causes far less eye fatigue even during long viewing sessions. Furthermore, e-paper possesses a bistable characteristic, meaning it only consumes power when the displayed image changes, making it significantly more energy-efficient than traditional self-luminous displays. In short, e-paper combines the advantages of both conventional displays and printed paper: it can update its content at any time while retaining the visual and reading experience of real paper.<\/p>\n\n\n\n

Microcup electrophoretic ink and ChLCD are the two most promising color e-paper technologies<\/a> at present. The following section provides a brief introduction to each. To effectively analyze the colors of e-paper, this article uses the ICC color profile format defined by the International Color Consortium (ICC) to visualize and analyze the color gamut characteristics and luminance contrast of color e-paper.<\/p>\n\n\n\n

The leading manufacturer of ChLCD<\/a> is IRIS Optronics. In this type of e-paper, cholesteric liquid crystal molecules inside the panel are driven by an electric field that adjusts the opening and closing angle of the liquid crystal layers to display images. The display is composed of three stacked cholesteric liquid crystal layers, each capable of reflecting one of the three primary colors: Red (R), Green (G), and Blue (B). By varying the strength of the electric field, the liquid crystal molecules within each layer are made to rotate. Even after the electric field is turned off, the liquid crystal molecules remain in one of two stable states, enabling bistability.<\/p>\n\n\n