US3792267A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic x-ray exposure device
Assignee: US Philips Corp
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Filing: 1971-12-03
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Granted: 1974-02-12
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Expires: 1991-12-03
Abstract
Abstract An automatic X-ray exposure device includes a radiation detector which supplies an output current proportional to the amount of Xray energy impinging upon the film. An integrating circuit is responsive thereto to produce a signal corresponding to the accumulated X-ray energy on the film. A logarithmic amplifier is connected to the integrating circuit so as to derive a control signal proportional to the logarithm of the integrated signal. The control signal is used to automatically terminate the X-ray exposure.
Inventors
- 👤 K Westerkowsky
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 06:42
CPC Classifications
H; H05; H05G; H05G1/00; H05G1/08; H05G1/26; H05G1/30; H05G1/38; H05G1/42; H05G1/44
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
112 words
An automatic X-ray exposure device for triggering a control device to terminate an X-ray exposure comprising, a radiation detector arranged between an object to be radiographed and an Xray film for generating a signal proportional to the X-ray energy dose impinging on the film, an integrating circuit coupled to the detector so as to derive a signal corresponding to the X-ray energy accumulated on the film, a logarithmic amplifier connected to the output of the integrating circuit so as to derive a control signal at the output of the amplifier which is proportional to the logarithm of the integrated output signal, and means for applying said control signal to the control device.
Claim 2
Dependent Claim
112 words
An automatic X-ray exposure device for triggering a control device to terminate an X-ray exposure comprising, a radiation detector arranged between an object to be radiographed and an Xray film for generating a signal proportional to the X-ray energy dose impinging on the film, an integrating circuit coupled to the detector so as to derive a signal corresponding to the X-ray energy accumulated on the film, a logarithmic amplifier connected to the output of the integrating circuit so as to derive a control signal at the output of the amplifier which is proportional to the logarithm of the integrated output signal, and means for applying said control signal to the control device.
Claim 3
Dependent Claim
61 words
An automatic X-ray exposure device as claimed in claim 1 further comprising means for biasing the logarithmic amplfier to a threshold voltage that is proportional to a reference value of X-ray dose so that the amplifier only provides said control signal after the reference dose is exceeded, said reference dose being approximately 10 percent smaller than the lowest X-ray dose required.
Claim 4
Dependent Claim
43 words
An automatic X-ray exposure device as claimed in claim 1 further comprising a quantizing device coupled to the amplifier output for quantizing the control signal, said quantizing device generating a number of pulses which is proportional to the amplitude of the control signal.
Claim 5
Dependent Claim
44 words
An automatic X-ray exposure device as claimed in claim 3, characterized in that the quantizing device is arranged so that the duration of the pulses supplied therefrom is less than the smallest time interval between two pulses to be anticipated at maximum dose power.
Claim 6
Dependent Claim
102 words
An automatic X-ray exposure device as claimed in claim 3 wherein said quantizing device comprises, a capacitor, a resistor, a threshold-value switch having an adjustable threshold value, means for coupling the control signal to the input of the switch via the series connection of said capacitor and resistor, said threshold-value switch being arranged to supply a pulse of a given duration when said adjustable threshold value is exceeded, means for applying said pulse to a transistor to drive same into conduction, and means connecting the transistor in circuit so that the capacitor is charged to the instantaneous value of the control signal.
Claim 7
Dependent Claim
65 words
An automatic X-ray exposure device as claimed in claim 3 further comprising means for applying the pulses to a counter which provides an output signal to activate the control device for terminating the exposure when a given count is reached in the counter, and a presetting device connected to the counter to adjust the value of the given count that will produce said output signal.
Claim 8
Dependent Claim
34 words
An automatic X-ray exposure device as claimed in claim 1 wherein said control signal applying means comprises pulse generating means for generating a number of pulses porportional to the amplitude of the control signal.
Claim 9
Dependent Claim
83 words
An automatic X-ray exposure device as claimed in claim 7 wherein said pulse generating means comprises, a capacitor, switching means having a threshold value at which it is activated, means for coupling the control signal to the input of the switching means via said capacitor, and means coupled to the capacitor and controlled by the output signal of the switching means for charging the capacitor to the instantaneous value of the control signal when the switching means is activated by the control signal.
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) | 1977-02-11 | 1977-08-13 | 1978-02-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-02-11 | 1981-08-13 | 1982-02-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-02-11 | 1985-08-13 | 1986-02-12 | $7700.00 | Window Closed / Lapsed |