US5611958A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Infrared phosphor and material having latent images and optical reading system using said phosphor
Assignee: Maxell Ltd
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Filing: 1994-05-04
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Granted: 1997-03-18
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Expires: 2014-05-04
Abstract
Abstract The invention provides a phosphor excited by infrared rays to emit infrared rays which has a nonacicular particle shape and a particle size of 4 mu m or smaller after being synthesized. The phosphor preferably comprises an oxoacid salt-containing compound including at least one element selected from the group consisting of Nd, Yb and Er. The invention further provides a material having a latent image pattern comprising said phosphor and an optical reading system which use the material having a latent image pattern.
Inventors
- 👤 Yoji Takeuchi
- 👤 Toshio Oshima
- 👤 Ryuzo Fukao
- 👤 Hisao Kanzaki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 07:34
CPC Classifications
C; C09; C09K; C09K11/00; C09K11/08; C09K11/77; C09K11/7709; C09K11/7701; C09K11/7756; C09K11/7766; C09K11/7767; C09K11/7769; C09K11/7777; G; G06; G06K; G06K19/00; G06K19/06; G06K19/06009; G06K19/06046; G06K7/00; G06K7/10; G06K7/12; B; B41; B41M; B41M3/00; B41M3/14; B41M3/144; Y; Y10; Y10S; Y10S428/00; Y10S428/913
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
90 words
An infrared phosphor having nonacicularly-shaped particles that are less than or equal to 4 μm in size, the phosphor being stimulated to phosphoresce by infrared light, the infrared phosphor comprising a phosphate compound represented by the following formula: Ln.sub.x B.sub.1-x PO.sub.4 wherein: B represents at least one element selected from the group consisting of Y, La, Gd, Bi, Ce, Lu, In, Pr and Tb; Ln represents at least one element selected from the group consisting of Nd; Yb and Er; and x is a numerical value of 0.01 to 0.99.
Claim 2
Dependent Claim
90 words
An infrared phosphor having nonacicularly-shaped particles that are less than or equal to 4 μm in size, the phosphor being stimulated to phosphoresce by infrared light, the infrared phosphor comprising a phosphate compound represented by the following formula: Ln.sub.x B.sub.1-x PO.sub.4 wherein: B represents at least one element selected from the group consisting of Y, La, Gd, Bi, Ce, Lu, In, Pr and Tb; Ln represents at least one element selected from the group consisting of Nd; Yb and Er; and x is a numerical value of 0.01 to 0.99.
Claim 3
Dependent Claim
23 words
A phosphor as in claim 1, wherein: the phosphor, when stimulated by infrared light, phosphoresces in the range of 800 to 1600 nm.
Claim 4
Dependent Claim
24 words
An infrared phosphor according to claim 1, wherein the wavelength of the exciting light coincides with that of the emitted light at room temperature.
Claim 5
Dependent Claim
115 words
A material having a latent image comprising: a substrate; and a print layer on the substrate; the print layer including: an infrared phosphor having nonacicularly-shaped particles that are less than or equal to 4 μm in size, the phosphor being stimulated to phosphoresce by infrared light; and a binder; wherein the infrared phosphor comprises a phosphate compound represented by the following formula: Ln.sub.x B.sub.1-x PO.sub.4 and wherein: B represents at least one element selected from the group consisting of Y, La, Gd, Bi, Ce, Lu, In, Pr and Tb; Ln represents at least one element selected from the group consisting of Nd, Yb and Er; and x is a numerical value of 0.01 to 0.99.
Claim 6
Dependent Claim
115 words
A material having a latent image comprising: a substrate; and a print layer on the substrate; the print layer including: an infrared phosphor having nonacicularly-shaped particles that are less than or equal to 4 μm in size, the phosphor being stimulated to phosphoresce by infrared light; and a binder; wherein the infrared phosphor comprises a phosphate compound represented by the following formula: Ln.sub.x B.sub.1-x PO.sub.4 and wherein: B represents at least one element selected from the group consisting of Y, La, Gd, Bi, Ce, Lu, In, Pr and Tb; Ln represents at least one element selected from the group consisting of Nd, Yb and Er; and x is a numerical value of 0.01 to 0.99.
Claim 7
Dependent Claim
27 words
A material having a latent image according to claim 4, wherein the wavelength of the exciting light coincides with that of the emitted light at room temperature.
Claim 8
Dependent Claim
27 words
A material having a latent image according to claim 4, wherein thickness of the infrared exciting print layer is in the range of 0.5 to 50 μm.
Claim 9
Dependent Claim
30 words
A material having a latent image according to claim 4, wherein light reflectance of the surface of the substrate on which the print layer is provided is 20% or higher.
Claim 10
Dependent Claim
23 words
A material as in claim 4, wherein: the phosphor, when stimulated by infrared light, phosphoresces in the range of 800 to 1600 nm.
Claim 11
Dependent Claim
158 words
An optical reading system for detecting phosphorescence of a marking substance on an object, the system comprising: an infrared light emitter; a marking substance on the object, the marking substance including an infrared phosphor having nonacicularly-shaped particles that are less than or equal to 4 μm in size, the phosphor being stimulated to phosphoresce by the infrared light from the light emitter; and a light detector, the light detector operating after the light emitter turns off so as to detect the phosphorescence from the phosphor; wherein the infrared phosphor of the marking substance on the object comprises a phosphated compound represented by the following formula: Ln.sub.x B.sub.1-x PO.sub.4 and wherein: B represents at least one element selected from the group consisting of Y, La, Gd, Bi; Ce; Lu, In, Pr and Tb; Ln represent at least one element selected from the group consisting of Nd, Yb and Er; and x is a numerical value of 0.01 to 0.99.
Claim 12
Dependent Claim
158 words
An optical reading system for detecting phosphorescence of a marking substance on an object, the system comprising: an infrared light emitter; a marking substance on the object, the marking substance including an infrared phosphor having nonacicularly-shaped particles that are less than or equal to 4 μm in size, the phosphor being stimulated to phosphoresce by the infrared light from the light emitter; and a light detector, the light detector operating after the light emitter turns off so as to detect the phosphorescence from the phosphor; wherein the infrared phosphor of the marking substance on the object comprises a phosphated compound represented by the following formula: Ln.sub.x B.sub.1-x PO.sub.4 and wherein: B represents at least one element selected from the group consisting of Y, La, Gd, Bi; Ce; Lu, In, Pr and Tb; Ln represent at least one element selected from the group consisting of Nd, Yb and Er; and x is a numerical value of 0.01 to 0.99.
Claim 13
Dependent Claim
29 words
An optical reading system as in claim 9, wherein: the phosphor, when stimulated by infrared light from the light emitter, phosphoresces in the range of 800 to 1600 nm.
Claim 14
Dependent Claim
25 words
An optical reading system according to claim 9, wherein the wavelength of the exciting light coincides with that of the emitted light at room temperature.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-03-17 | 2000-09-16 | 2001-03-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-03-17 | 2004-09-16 | 2005-03-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-03-17 | 2008-09-16 | 2009-03-18 | $7700.00 | Window Closed / Lapsed |