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US4472635A Expired / Lapsed US ⏱️ 0.0 years remaining

Radiographic intensifying screen

Assignee: Toshiba Corp
•
Filing: 1982-09-28
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Granted: 1984-09-18
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Expires: 2002-09-28
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Abstract

Abstract A radiographic intensifying screen having improved modulation transfer function and/or sensitivity. The radiographic intensifying screen of the present invention comprises a support, a phosphor layer formed on the support, a protective film formed on the phosphor layer, wherein the phosphor layer includes a small phosphor particles layer at its support side consisting essentially of small phosphor particles with an average grain size of about 4 μm or less and a binding agent; and a mixed large and small phosphor particles layer at its protective film side consisting essentially of large phosphor particles with an average grain size ranging from about 7 to 20 μm, small phosphor particles present in the interstices of the large phosphor particles and with an average grain size of about 4 μm or less and a binding agent.

Inventors

  • 👤 Kazuto Yokota
  • 👤 Mitsuo Nakamura

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-29 01:27
CPC Classifications
G; G21; G21K; G21K4/00

Claims Analysis

Total Claims: 6
Claim 1
Independent Claim 113 words
A radiographic intensifying screen comprising: a support; a phosphor layer formed on said support; and a protective film formed on said phosphor layer, wherein said phosphor layer includes: a small particles layer at its support side consisting essentially of small phosphor particles with an average grain size of about 4 μm or less and a binding agent; and a mixed particles layer at its protective film side consisting essentially of large phosphor particles with an average grain size ranging from about 7 to 20 μm, small phosphor particles present in the interstices of the large phosphor particles and with an average grain size of about 4 μm or less and a binding agent.
Claim 2
Dependent Claim 113 words
A radiographic intensifying screen comprising: a support; a phosphor layer formed on said support; and a protective film formed on said phosphor layer, wherein said phosphor layer includes: a small particles layer at its support side consisting essentially of small phosphor particles with an average grain size of about 4 μm or less and a binding agent; and a mixed particles layer at its protective film side consisting essentially of large phosphor particles with an average grain size ranging from about 7 to 20 μm, small phosphor particles present in the interstices of the large phosphor particles and with an average grain size of about 4 μm or less and a binding agent.
Claim 3
Dependent Claim 25 words
The radiographic intensifying screen according to claim 1, wherein the average grain size of said large phosphor particles ranges from about 7 to 12 μm.
Claim 4
Dependent Claim 34 words
The radiographic intensifying screen according to claim 1 or 2, wherein the weight ratio of said large phosphor particles to said small phosphor particles in said phosphor layer ranges from about 2:8 to 8:2.
Claim 5
Dependent Claim 22 words
The radiographic intensifying screen according to claim 3, wherein the thickness of said phosphor layer ranges from about 50 to 400 μm.
Claim 6
Dependent Claim 33 words
The radiographic intensifying screen according to claim 1, wherein the weight ratio of said large phosphor particles to said small phosphor particles in said mixed particles layer ranges from about 85:15 to 95:15.

References Cited (Backward Citations)

US2243828A Cited
US2310852A Cited
US2412654A Cited
US4088894A Cited
US4316092A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1987-09-18 1988-03-19 1988-09-18 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1991-09-18 1992-03-19 1992-09-18 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1995-09-18 1996-03-19 1996-09-18 $7700.00 Window Closed / Lapsed

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