Laser-addressed full-color photo-quality rewritable sheets based on thermochromic systems with leuco dyes

摘要

We have developed a laser-addressed full-color photographic quality rewritable sheet. The sheet was composed of a vertically stacked Cyan/Magenta/Yellow-thermochromic system with a mixture of leuco dyes, developers and photothermal conversion agents in a polymer matrix. The sheet was simply manufactured by roll-to-roll (R2R) processes. Writing and erasing were performed by scan of near-infrared laser light. It achieved full-color photographic quality images with a wide color gamut with 70% coverage of the Specifications for Web Offset Publications (SWOP) standards and a high resolution of 426 ppi. Clear rewritability has also been confirmed. Non-contact laser writing has other advantages in that it can create an image under a protection film, and it has form factor flexibility. We have developed a reliability model for high-temperature storage and a light fastness test. This model showed a good agreement with experimental data, and the lifetime of an image was estimated to be over 8 years under ambient conditions. This technology will create applications for on-demand rewritable image design while saving power and reducing the use of paper, which will eventually contribute to a sustainable society.