Fluorescent substance, fluorescent composition, fluorescent mark carrier and optical reader therefor

• US 6,688,789 B2
• Filed: 05/16/2001
• Issued: 02/10/2004
• 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): Funk, Stephen R.
• Application Number:
  US09/855,545
• Publication Number:
  US 20010031163A1
• Time in Patent Office: 1,000 Days
• Field of Search: 400/241, 400/242, 400/241.1, 400/241.4, 101/491, 101/483, 347/241, 347/234, 428/484, 428/488.1, 428/690, 428/913, 428/914
• US Class Current: 400/241
• 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

An inked ribbon containing a tape-like carrier deposited with a fluorescent composition that contains a fluorescent substance containing at least one of Nd and Yb as an optical active element and, other than this optical active element, at least one oxide of one of Mo and W and an alkaline earth metal, which fluorescent substance is dispersed and retained in an organic binder, wherein the organic binder is a mixture of wax and resin, and wherein the fluorescent substance has an average particle size of not more than 1 micron.

Claims

1. An inked ribbon characterized in that it comprises a tape-like carrier deposited with a fluorescent composition comprising a fluorescent substance containing at least one of Nd and Yb as an optical active element and, other than this optical active element, at least one oxide of one of Mo and W and an alkaline earth metal, which fluorescent substance is dispersed and retained in an organic binder, wherein the organic binder is a mixture of wax and resin, and wherein the fluorescent substance has an average particle size of not more than 1 micron.

2. The inked ribbon as defined in claim 1, wherein the length of time required for the intensity of an afterglow, emitted by the fluorescent substance, to attain 10% of the maximum intensity of a fluorescent light subsequent to interruption of irradiation of an exciting light is within 500 μ

sec.

3. The inked ribbon as defined in claim 1, wherein the yield of the fluorescent substance when the fluorescent substance is immersed in water for 500 hours and is subsequently dried after removal from the water is not smaller than 95 wt %.

4. The inked ribbon as defined in claim 1, wherein the atomic ratio of the optical active element relative to at least one oxide of Mo or W is higher than zero, but equal to or lower than 2.

5. The inked ribbon as defined in claim 1, wherein the atomic ratio of the alkaline earth metal relative to at least one oxide of Mo or W is higher than zero, but equal to or lower than 3.

6. The inked ribbon as defined in claim 1, wherein the fluorescent substance has the following general formula:

7. The inked ribbon as defined in claim 1, wherein the fluorescent substance has the following general formula:

8. The inked ribbon as defined in claim 7, wherein X and Y in the general formula are within the range of 0.02 to 0.6 and within the range of ⅓

to {fraction (5/3)}, respectively.

9. The inked ribbon as defined in claim 1, wherein the alkaline earth metal is Ca.

10. The inked ribbon as defined in claim 1, wherein the resin is at least one selected from the group consisting of a copolymer of polyvinyl chloride and vinyl acetate, a copolymer of ethylene and vinyl acetate, polyester resin, polyurethane resin and polycarbonate resin.