US3752995A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Blank value storing photometer
Assignee: Coulter Electronics Inc
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Filing: 1972-04-07
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Granted: 1973-08-14
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Expires: 1992-04-07
Abstract
Abstract Circuitry which permits an externally supplied blanking solution, such as a serum blank, to be electronically stored for a long period of time, during which a calibration control solution and then a sequence of samples are applied to the photometer for calibration of the photometer and measurement of the sample in a logarithmic rundown mode. Specific subcircuits enhance the storing, calibrating and measuring operations.
Inventors
- 👤 G Liedholz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 09:15
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/17; G01N21/25; G01N21/27; G01N21/274
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
253 words
Blank storing photometer circuitry capable of receiving photometrically transduced signals from a photoresponsive element comprising: first and second multi-function amplifiers having inputs and outputs, a first switch coupling the output of said first amplifier to an input of said second amplifier, voltage rundown circuit means, a second switch coupling the output of said second amplifier to said rundown circuit means, blank value storing means coupled to said second amplifier, a feedback path coupling said rundown circuit means to one input of said first amplifier, a second input of said first amplifier connected to receive photometrically transduced signals, and control circuits for controlling the operation of said first and second switches and thereby defining three operating modes as well as generating a measurement of the photometrically transduced signals based upon their voltage rundown, said three operating modes being: a blank storage mode during which both said amplifiers act as amplifiers, both said switches are in a first state and said blank storing means stores the blank value; a calibration mode during which said first amplifier acts as a comparator between the stored blank value and a then being applied calibration value which is being rundown, the second amplifier and blank storing means coact to define a blank storage circuit, and said switches are in a second state; and a sample measuring mode which is substantially the same as said calibration mode, except that the comparison is between the stored blank value and one of a plurality of sample values then being applied and rundown.
Claim 2
Dependent Claim
253 words
Blank storing photometer circuitry capable of receiving photometrically transduced signals from a photoresponsive element comprising: first and second multi-function amplifiers having inputs and outputs, a first switch coupling the output of said first amplifier to an input of said second amplifier, voltage rundown circuit means, a second switch coupling the output of said second amplifier to said rundown circuit means, blank value storing means coupled to said second amplifier, a feedback path coupling said rundown circuit means to one input of said first amplifier, a second input of said first amplifier connected to receive photometrically transduced signals, and control circuits for controlling the operation of said first and second switches and thereby defining three operating modes as well as generating a measurement of the photometrically transduced signals based upon their voltage rundown, said three operating modes being: a blank storage mode during which both said amplifiers act as amplifiers, both said switches are in a first state and said blank storing means stores the blank value; a calibration mode during which said first amplifier acts as a comparator between the stored blank value and a then being applied calibration value which is being rundown, the second amplifier and blank storing means coact to define a blank storage circuit, and said switches are in a second state; and a sample measuring mode which is substantially the same as said calibration mode, except that the comparison is between the stored blank value and one of a plurality of sample values then being applied and rundown.
Claim 3
Dependent Claim
93 words
Blank storing photometer circuitry according to claim 1 in which said switch control circuits include a generator of a train of pulses for periodically opening said second switch to commence the rundown of the calibration value, and said control circuits further include means coupled to the output of said first amplifier responsive to its comparator operation for closing said second switch at the time when the rundown provides an equality comparison, the next following pulse of the generated train then opening the second switch, whereby a sequence of calibration value measurements are attained.
Claim 4
Dependent Claim
32 words
Blank storing photometer circuitry according to claim 2 in which said rundown circuit means comprises an R-C circuit, which is provided with an adjustment means for use during said calibration value measurements.
Claim 5
Dependent Claim
34 words
Blank storing photometer circuitry according to claim 1 in which compensating means for increasing the accurate responsiveness of said first amplifier to the beginning of the voltage rundown are coupled to said feedback path.
Claim 6
Dependent Claim
27 words
Blank storing photometer circuitry according to claim 4 in which said compensating means includes capacitive means for providing a high frequency response improvement to said first amplifier.
Claim 7
Dependent Claim
28 words
Blank storing photometer circuitry according to claim 4 in which said compensating means includes pulse means for producing a high-frequency rich pulse at the beginning of each rundown.
Claim 8
Dependent Claim
32 words
Blank storing photometer circuitry according to claim 6 in which said pulse means includes a capacitor which receives a trigger pulse from said switch control circuits at the beginning of each rundown.
Claim 9
Dependent Claim
41 words
Blank storing photometer circuitry according to claim 1 including signal attenuating means coupled between the output of said first amplifier and said first switch for preventing inadvertent switching action of said first switch during the comparator operation of said first amplifier.
Claim 10
Dependent Claim
17 words
Blank storing photometer circuitry according to claim 8 in which said attenuating means comprises a voltage divider.
Claim 11
Dependent Claim
39 words
Blank storing photometer circuitry according to claim 1 in which drift compensating means is connected to said one input of said first amplifier, said drift compensating means being constructed and connected to utilize existing drift in its compensating action.
Claim 12
Dependent Claim
29 words
Blank storing photometer circuitry according to claim 10 in which said drift compensating means comprises a voltage divider, at least part of which is connected into said feedback path.
Claim 13
Dependent Claim
25 words
Blank storing photometer circuitry according to claim 11 in which said voltage divider is of the resistive type having two legs of slightly different resistance.
Claim 14
Dependent Claim
44 words
Blank storing photometer circuitry according to claim 1 in which said switch control circuits include switch control logic having inputs separately responsive to said three operating modes, a first output coupled to said first switch and a second output coupled to said second switch.
Claim 15
Dependent Claim
46 words
Blank storing photometer circuitry according to claim 13 in which a flip-flop is interposed between said second output and said second switch, and a clock is provided which has one output controlled by said switch control logic to feed into said flip-flop during the calibration mode.
Claim 16
Dependent Claim
72 words
Blank storing photometer circuitry according to claim 14 in which said clock has another output which is not controlled by said switch control logic and a gate is provided with one input from said another output and a second input from said flip-flop, such second input enabling said gate during voltage rundown, whereby the number of gated clock pulses is a digitalized measure of the transduced signals received by said first amplifier.
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) | 1976-08-13 | 1977-02-12 | 1977-08-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-08-13 | 1981-02-12 | 1981-08-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-08-13 | 1985-02-12 | 1985-08-14 | $7700.00 | Window Closed / Lapsed |