Blood glucose reflectance meter including a null prompting means and a device for providing a constant brightness light
First Claim
1. In a portable blood glucose monitoring meter having an analog circuit with a variable potentiometer to measure blood glucose-induced changes in the chemistries of disposable test strips to determine blood glucose concentrations, the improvements comprising:
- dial means to vary manually the resistance of said potentiometer to locate a null position that balances the measure of the blood glucose-induced changes in the chemistries of disposable test strips;
calibration means integral with said dial means to receive replaceable, pre-printed, man-readable blood glucose concentrations that correspond to the null positions located by said dial means and that are empirically calibrated to the batch lot variations in the chemistries of the disposable test strips used in the meter; and
null prompting means to indicate the manual variation of said dial means required to achieve a null position.
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Accused Products
Abstract
A portable blood glucose monitoring meter that employs an analog circuit in conjunction with a manually rotatable dial that varies the resistance of a potentiometer to locate a null position that balances the measure taken of the blood glucose-induced changes in the chemistries of disposable test strips. The dial supports a replaceable, pre-printed, man-readable calibration disk. The calibration disk displays in man-readable format blood glucose concentrations in milligrams per milliliter calibrated to the specific batch-lot chemistries of the disposable test strips used with the meter. A patient places a replaceable batch-lot calibration disk upon the dial, and inserts a corresponding test strip bearing a drop of capillary blood into the meter. The patient then manually adjusts the dial until prompting arrows indicate a null position. If the dial has rotated past the null position, an opposing arrow will illuminate indicating a need to rotate the dial in the opposite direction. The procedure is repeated until a null position is found. At the null position, the prompting arrows illuminate simultaneously. The concentration of the patient'"'"'s blood glucose in milligrams per milliliter is then read directly from the number appearing on the calibration disk at the null point.
53 Citations
14 Claims
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1. In a portable blood glucose monitoring meter having an analog circuit with a variable potentiometer to measure blood glucose-induced changes in the chemistries of disposable test strips to determine blood glucose concentrations, the improvements comprising:
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dial means to vary manually the resistance of said potentiometer to locate a null position that balances the measure of the blood glucose-induced changes in the chemistries of disposable test strips; calibration means integral with said dial means to receive replaceable, pre-printed, man-readable blood glucose concentrations that correspond to the null positions located by said dial means and that are empirically calibrated to the batch lot variations in the chemistries of the disposable test strips used in the meter; and null prompting means to indicate the manual variation of said dial means required to achieve a null position. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. In a portable reflectance meter having an analog circuit with a potentiometer, the meter providing a measurement of color variances resulting from test solutions deposited on disposable chemically treated test strips to determine chemical concentrations of certain chemicals contained in the test solutions, the improvements comprising:
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dial means for manually varying the resistance of said potentiometer to locate a null position that balances color changes of the disposable test strips against a reference; calibration means integral with said dial means to receive replaceable, pre-printed, man-readable chemical concentration disks that correspond with the null position located by said dial means and that are empirically calibrated to correspond with the chemical characteristics of a particular batch of the disposable test strips used in the meter; a light emitting diode for illuminating the chemically treated test strips; first circuit means connected to said light emitting diode for providing a current signal to said light emitting diode, said current signal varying in accordance with variations in ambient temperature to maintain a constant intensity brightness signal from said light emitting diode; and null prompting means for indicating to the user the manual variation of said dial means required to achieve a null position. - View Dependent Claims (11, 12, 13)
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14. A device for providing a constant brightness light signal comprising:
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temperature compensation means for producing a temperature signal wherein said temperature compensation means is a diode and said temperature signal is the forward voltage drop across said diode; power source means responsive to said temperature signal for producing a power signal in accordance with said temperature signal wherein said power source means includes an operational amplifier and a transistor wherein the diode is forward biased with the cathode of the diode connected to an input of the operational amplifier, wherein said transistor is connected in a feedback loop with said operational amplifier with the base of the transistor connected to the output of said operational amplifier, and wherein the transistor produces the power signal; and
a light emitting diode responsive to said power signal and producing a constant intensity light signal in response thereto.
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Specification