Neodymium, ytterbium and/or erbium containing organic fluorescent compositions

• US 6,471,887 B2
• Filed: 05/16/2001
• Issued: 10/29/2002
• Est. Priority Date: 03/17/1994
• Status: Expired due to Fees

• Current Assignee: Hitachi Maxell Limited (Maxell, Ltd.)
• Original Assignee: Hitachi Maxell Limited (Maxell, Ltd.)
• Inventors: Yamada, Yukinori, Kamoto, Takanori, Saibara, Shoji, Oshima, Toshio, Nabeshima, Tomio
• Primary Examiner(s): KOSLOW, CAROL M
• Application Number:
  US09/855,540
• Publication Number:
  US 20010030313A1
• Time in Patent Office: 531 Days
• Field of Search: 252/301.16, 252/301.34, 252/301.35, 106/31.15, 106/31.32, 106/31.64
• US Class Current: 252/301.16
• CPC Class Codes: C09D 11/50 Sympathetic, colour changing or similar inks
• CPC Class Codes: C09K 11/02 Use of particular materials as binders, particle coatings or suspension media therefor
• CPC Class Codes: C09K 11/06 containing organic luminescent materials
• CPC Class Codes: C09K 11/08 containing inorganic luminescent materials
• CPC Class Codes: C09K 11/7701 Chalogenides
• CPC Class Codes: C09K 11/7706 Aluminates
• CPC Class Codes: C09K 11/7708 Vanadates; Chromates; Molybdates; Tungstates
• CPC Class Codes: C09K 11/7709 Phosphates
• CPC Class Codes: C09K 11/7756 containing neodynium
• CPC Class Codes: C09K 11/7769 Oxides C09K11/7768 takes precedence
• CPC Class Codes: C09K 11/7774 Aluminates
• CPC Class Codes: C09K 11/7776 Vanadates; Chromates; Molybdates; Tungstates
• CPC Class Codes: C09K 11/7777 Phosphates

Abstract

A fluorescent substance of the following general formula:

Ln_xA_1−XPO₄

wherein Ln represents at least one element selected from the group consisting of Nd, Yb and Er; A represents at least one element selected from the group consisting of Y, La, Gd, Bi, Ce, Lu, In and Tb; and X represents a value within the range of 0.01 to 0.99.

Claims

1. A fluorescent substance characterized in that it comprises at least one organic substance containing a rare earth element selected from the group consisting of Nd, Yb and/or Er, and is combined with at least one organic substance having at least one absorption band within the infrared region of light.

2. The fluorescent substance as defined in claim 1, characterized in that it comprises an aromatic carboxylic acid salt containing at least one rare earth element selected from the group consisting of Nd, Yb and/or Er and the at least one organic substance is capable of absorbing light of a wavelength within the range of 700 to 1,000 nm.

3. The fluorescent substance as defined in claim 1, characterized in that at least the organic substance having at least one absorption band within the infrared region of light is selected from the group consisting of polymethine, anthraquinone, diothiol metal, phthalocyanine, indophenol, azo dyestuff, and mixtures thereof.

4. A fluorescent composition characterized in that it comprises a fluorescent substance containing at least one organic substance containing a rare earth element selected from the group consisting of Nd, Yb and/or Er, and is combined with at least one organic substance having at least one absorption band within the infrared region of light, and an organic binder.