An aqueous formulation comprises a sulfonated water-soluble IR-absorbing naphthalocyanine dye having a central metal atom moiety. A pH of the formulation is in the range of 4 to 6.5, which minimizes visibility of the formulation....http://www.google.com.tw/patents/US20110023751?utm_source=gb-gplus-share專利 US20110023751 - AQUEOUS FORMULATION COMPRISING LOW VISIBILITY NAPHTHALOCYANINE DYE
