Patent US4740683A successfully refreshed from Google Patents.
US4740683A
Expired / Lapsed
US
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X-ray image intensifier with phosphor layer of varying thickness
Assignee: Toshiba Corp
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Filing: 1987-03-30
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Granted: 1988-04-26
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Expires: 2007-03-30
Abstract
Abstract An X-ray image intensifier includes an input surface and an output surface facing the input surface. The input surface has a base and a phosphor layer formed on the base and having a predetermined effective radius. The phosphor layer includes a thickest portion which has a thickness about 105 to 115% of a thickness of a center of the layer and is located in a region spaced from the center toward the periphery of the layer by a distance about 60 to 80% of the effective radius. The phosphor layer is formed so that the thickness is gradually increased from the center to the thickest portion and a region between the thickest portion and the periphery of the layer has a thickness about 50 to 100% of the thickness of the thickest portion.
Inventors
- 👤 Takashi Noji
- 👤 Shigeharu Kawamura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 18:25
CPC Classifications
H; H01; H01J; H01J29/00; H01J29/02; H01J29/10; H01J29/36; H01J29/38; H01J29/385
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
176 words
An X-ray image intensifier comprising: a substantially cylindrical housing having two closed ends; a circular input surface arranged in the housing along one end thereof; an output surface arranged in the housing along the other end thereof and facing the input surface; and an electrode arranged in the housing between the input and output surfaces, wherein the input surface includes a base and a phosphor layer formed on the base and having a predetermined effective radius, and the phosphor layer includes a thickest portion which has a thickness about 105 to 115% of a thickness of a center of the phosphor layer and is located in a region separated from the center of the phosphor layer toward the periphery thereof by a distance about 60 to 80% of the effective radius, and is formed so that the thickness is gradually increased from the center to the thickest portion, and a region between the thickest portion and the periphery of the phosphor layer has a thickness about 50 to 100% of the thickness of the thickest portion.
Claim 2
Dependent Claim
176 words
An X-ray image intensifier comprising: a substantially cylindrical housing having two closed ends; a circular input surface arranged in the housing along one end thereof; an output surface arranged in the housing along the other end thereof and facing the input surface; and an electrode arranged in the housing between the input and output surfaces, wherein the input surface includes a base and a phosphor layer formed on the base and having a predetermined effective radius, and the phosphor layer includes a thickest portion which has a thickness about 105 to 115% of a thickness of a center of the phosphor layer and is located in a region separated from the center of the phosphor layer toward the periphery thereof by a distance about 60 to 80% of the effective radius, and is formed so that the thickness is gradually increased from the center to the thickest portion, and a region between the thickest portion and the periphery of the phosphor layer has a thickness about 50 to 100% of the thickness of the thickest portion.
Claim 3
Dependent Claim
26 words
An X-ray image intensifier according to claim 1, wherein the thickness of the center of said phosphor layer is set to be 230 to 530 μm.
Claim 4
Dependent Claim
40 words
An X-ray image intensifier according to claim 1, wherein the thickness of said phosphor layer is increased at a rate of 0.2 to 1.5 μm/cm from the center to the thickest portion along the radial direction of the phosphor layer.
Claim 5
Dependent Claim
40 words
An X-ray image intensifier according to claim 1, wherein the thickness of said phosphor layer is decreased at a rate of 0 to 7 μm from the thickest portion to the periphery along the radial direction of the phosphor layer.
Claim 6
Dependent Claim
19 words
An X-ray image intensifier according to claim 1, wherein said phosphor layer consists of an alkali halide deposition film.
Claim 7
Dependent Claim
24 words
An X-ray image intensifier according to claim 1, wherein said phosphor layer consists of columnar crystals having a diameter of 15 μm or less.
Claim 8
Dependent Claim
57 words
An X-ray image intensifier according to claim 1, wherein said input surface includes a normal visual field having the same radius as the effective radius of the phosphor layer, and a second visual field having a radius smaller than the radius of the normal visual field, and the thickest portion is located outside the second visual field.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-04-26 | 1991-10-26 | 1992-04-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-04-26 | 1995-10-26 | 1996-04-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-04-26 | 1999-10-26 | 2000-04-26 | $7700.00 | Window Closed / Lapsed |