US4641331A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic exposure device for a panoramic X-ray photographing device
Assignee: J Morita Manufaturing Corp
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Filing: 1984-08-01
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Granted: 1987-02-03
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Expires: 2004-08-01
Abstract
Abstract An automatic exposure device for obtaining X-ray pictures with superior quality and constant contrast by feedback of both tube voltage and tube current according to the residual X-ray dose which penetrates the body of a patient. This device is further characterized in that the feedback control is compensatingly done according to the changes in the tube voltage and tube current caused by fluctuations of the power supply.
Inventors
- 👤 Takao Makino
- 👤 Shinichi Osada
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 09:24
CPC Classifications
H; H05; H05G; H05G1/00; H05G1/08; H05G1/26; H05G1/30; H05G1/46; H05G1/60
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
156 words
An automatic exposure device for a panoramic X-ray photographing apparatus comprising a means for converting a residual X-ray dose penetrating a patient and an X-ray film into an electrical output, a comparing means for comparing the level of said electrical output with a preset level, a tube voltage feedback control element provided at the primary side of a high voltage transformer, a tube current feedback control element provided at the primary side of a filament transformer, wherein both feedback control elements are simultaneously feedback-controlled by the output of said comparing means, and a means for detecting the feed speed of the X-ray film and converting the speed into an electrical output so that said electrical output of said residual penetrated X-ray dose and the electrical output of said feed speed may be simultaneously inputted to said comparing means and that the ratio of the two outputs may be delivered as the output of said comparing means.
Claim 2
Dependent Claim
156 words
An automatic exposure device for a panoramic X-ray photographing apparatus comprising a means for converting a residual X-ray dose penetrating a patient and an X-ray film into an electrical output, a comparing means for comparing the level of said electrical output with a preset level, a tube voltage feedback control element provided at the primary side of a high voltage transformer, a tube current feedback control element provided at the primary side of a filament transformer, wherein both feedback control elements are simultaneously feedback-controlled by the output of said comparing means, and a means for detecting the feed speed of the X-ray film and converting the speed into an electrical output so that said electrical output of said residual penetrated X-ray dose and the electrical output of said feed speed may be simultaneously inputted to said comparing means and that the ratio of the two outputs may be delivered as the output of said comparing means.
Claim 3
Dependent Claim
118 words
An automatic exposure device for a panoramic X-ray photographing apparatus comprising a means for converting the residual X-ray dose penetrating a patient and an X-ray film into an electrical output, first comparing means for comparing the level of said electrical output with a preset level, second comparing means for comparing the output level of the first comparing means with the actual tube voltage and current applied to an X-ray tube, a tube voltage feedback control element provided at the primary side of a high voltage transformer and a tube current feedback control element provided at the primary side of a filament transformer, wherein both feedback control elements are simultaneously feedback-controlled by the output of said second comparing means.
Claim 4
Dependent Claim
118 words
An automatic exposure device for a panoramic X-ray photographing apparatus comprising a means for converting the residual X-ray dose penetrating a patient and an X-ray film into an electrical output, first comparing means for comparing the level of said electrical output with a preset level, second comparing means for comparing the output level of the first comparing means with the actual tube voltage and current applied to an X-ray tube, a tube voltage feedback control element provided at the primary side of a high voltage transformer and a tube current feedback control element provided at the primary side of a filament transformer, wherein both feedback control elements are simultaneously feedback-controlled by the output of said second comparing means.
Claim 5
Dependent Claim
81 words
An automatic exposure device as defined in claim 2, wherein said exposure device further comprises a means for detecting the feed speed of the X-ray film and converting the speed into an electrical output so that the electrical output of said residual penetrated X-ray dose and the electrical output of said feed speed may be simultaneously input to said first comparing means and that the ratio of the two outputs may be delivered as the output of said first comparing means.
Claim 6
Dependent Claim
28 words
An automatic exposure device as defined in claim 1, 2 or 3, wherein transistors are used for said tube voltage feedback element and said tube current control element.
Claim 7
Dependent Claim
28 words
An automatic exposure device as defined in claim 1, 2 or 3, wherein thyristors are used for said tube voltage feedback element and said tube current control element.
Claim 8
Dependent Claim
28 words
An automatic exposure device as defined in claim 1, 2 or 3, wherein triacs are used for said tube voltage feedback element and said tube current control element.
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) | 1990-02-02 | 1990-08-04 | 1991-02-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-02-02 | 1994-08-04 | 1995-02-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-02-02 | 1998-08-04 | 1999-02-03 | $7700.00 | Window Closed / Lapsed |