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

• Published in: Journal of the Society for Information Display 2019-05, Vol.27 (5), p.295-303
• Main Authors: Kaino, Yuriko, Kurihara, Kenichi, Shuto, Aya, Mizuno, Hiroshi, Asaoka, Satoko, Ishida, Takehisa, Takagi, Kenji, Takahashi, Isao, Amago, Hirohisa, Takeuchi, Taichi, Tejima, Asuka, Watanabe, Maho, Oishi, Yuki, Kamei, Takahiro, Nomoto, Kazumasa
• Format: Article
• Language: English
• Subjects: Color; Developers; Energy conservation; Form factors; full color; high resolution; Image quality; Infrared lasers; Infrared photography; Infrared radiation; laser addressed; Lasers; leuco dye; Leuco dyes; Light fastness; Model testing; Photographic developers; photographic quality; Photothermal conversion; Protective coatings; Reliability analysis; Reliability aspects; rewritable sheet
• ISSN: 1071-0922; 1938-3657
• DOI: 10.1002/jsid.775

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. We have developed a laser‐addressed full‐color rewritable sheet based on a thermochromic system with leuco dyes. It achieved photographic quality images with a high resolution of 426 ppi and wide color gamut. Noncontact laser writing on free‐form sheets will create applications with on‐demand rewritable image design on various surfaces.