KR960016296B1 - Apparatus for measuring blood glucose - Google Patents

Abstract

a micom(1) outputting a control signal to display the calculated blood sugar value according to the light intensity; a pulse-voltage converting part(20) outputting a DC voltage corresponding to the pulse signal inputted from the micom(1); a sensor part(22) comprising an light-emitting means emitting a light corresponding to the output of the pulse-voltage converting part(20) and a current-generating means generating a current corresponding to the light reflected by the strip whose color is changed by the blood; a detecting part(21) outputting a detection signal corresponding to the current signal from the sensor part(22); and a displaying apparatus(2) displaying the blood sugar value.

Description

Automatic blood glucose meter with auto zero function

1 is a schematic configuration diagram of an automatic blood glucose measurement apparatus having an auto zero function according to an embodiment of the present invention.

2 is a detailed circuit diagram of an automatic blood glucose measurement apparatus having an auto zero function according to an embodiment of the present invention.

3 is a graph showing the relationship between the sensor detection voltage and the blood glucose level used in the present invention.

4 is an operation flowchart of an automatic blood glucose measurement method having an auto zero function according to an embodiment of the present invention.

The present invention relates to an automatic blood glucose measurement apparatus having an automatic zero function and a method of measuring the same. More specifically, as a portable type, a blood glucose concentration of a user can be determined by providing a precise numerical value while being conveniently used anywhere. Automatic blood sugar device with automatic zero function and its measurement which can be used by non-experts and at the same time can calculate accurate measurement value by correcting the error of ambient light or electronic parts through auto zero function. It is about a method.

The general method used to determine the concentration of sugar contained in the blood is a method of visually judging how many sugars are low by seeing the discolored color of the strip containing enzymes that change color according to the concentration of sugar. It is not known and only shows the trend.

Since more accurate information about blood glucose requires highly precise instruments and is also specialized, it is difficult to implement a device suitable for the general public to use as a portable type. In addition, even if the portable blood glucose measurement apparatus is implemented, there is a problem that accurate measurement cannot be made due to the amount of ambient light or an error of an electronic component.

An object of the present invention is to solve the conventional problems as described above, by providing a precise numerical value that can be conveniently used without regard to the place as a portable type, the expert or non-expert who knows the blood sugar level of the user specifically In addition, the present invention provides an automatic blood glucose apparatus having an automatic zero function and a method of measuring the same, by calculating an accurate measurement value by correcting an error of an ambient light quantity or an electronic component through an automatic zero function.

As a means for achieving the above object, the configuration of the apparatus of the present invention includes a memory having a reference value stored therein, and light is emitted so that a current corresponding to the reference value can be detected through reflected light at an initial stage of operation. After performing the auto zero operation to adjust the pulse width of the pulse signal for emitting light so that the light, the blood glucose value is calculated according to the intensity of light measured from the reflected light by the discolored strip and outputs a control signal for displaying the same. A strip discolored by a microcomputer, a pulse-voltage converter for outputting a DC voltage corresponding to the pulse signal input from the microcomputer, a light emitting means for emitting light corresponding to the output of the pulse-voltage changing unit, and blood A sensor portion having means for receiving the light reflected by the light and generating a current corresponding thereto; A sensor signal detecting unit for receiving a current signal of the sensor and outputting a corresponding detection signal, and a blood glucose value corresponding to a data value obtained by converting the detection signal of the sensor signal detecting unit into a digital value, and a ROM table built in the microcomputer. And a display device for displaying the blood sugar level by calculating from the.

As a means for achieving the above object, the configuration of the method of the present invention is an automatic zero for matching the light intensity of the light emitting portion during initial operation with a reference value set between the upper and lower limits of the detection output of the sensor portion comprising the light emitting portion and the light receiving portion. Operation step; The sensor detects the strip that reacts with blood for a predetermined time after the auto-zero phase receives a first sensor voltage that generates a sensor voltage corresponding to a color discolored by the sensor unit and a second sensor detection voltage that is twice that voltage. Comparing with the center of voltage; Referring to the blood glucose level with respective resolutions for the lower limit section (first section) and the upper limit section (second section) based on the median value; And displaying data of a ROM table on a display device.

The device of the present invention, the color of the collected blood bite on the strip and then insert the strip into the sensor of the device automatically shows the blood glucose level as a numerical value, and also remembers the previous blood glucose measurement to be able to see again Compact, compact and lightweight, it is very convenient to use and carry.

Hereinafter, the most preferred embodiments of the present invention will be described with reference to the accompanying drawings so that those skilled in the art can easily implement the present invention.

1 is a schematic configuration diagram of an automatic blood glucose measurement apparatus having an auto zero function according to an embodiment of the present invention.

As shown in FIG. 1, the configuration of an automatic blood glucose measurement apparatus having an auto zero function according to an embodiment of the present invention includes a pulse signal having a pulse width proportional to the intensity of light from the microcomputer 1 and the microcomputer 1. A pulse-to-voltage converter 20 for receiving the light into a corresponding constant voltage, a light emitting diode (LED) that emits a corresponding light according to the output of the pulse-voltage converter 20, and receiving the light to generate a corresponding current. A ROM table built in the microcomputer 1 so as to obtain a corresponding blood sugar level using a sensor unit 22 composed of a photodiode, a sensor signal detector 21 that receives a sensor signal, and outputs a corresponding voltage. The display section 2 outputs data from the display.

In addition, since the apparatus of the present invention is a portable type, a small battery is provided as the power supply unit 4 to supply power to the microcomputer 1 and the peripheral circuits. In addition, since the microcomputer 1 requires a clock signal, a clock generator 5 including a crystal oscillator is provided.

Then, the user has two keys (SW1, SW2) for instructing the operation of the device after inserting the strip (S) into the sensor unit 22, according to the on and off of the keys (SW1, SW2) described above. The device works properly. One of them is the power key to turn on the device and the other is the start key for the measurement start indication. However, it is not necessarily used only as a power key and a start key, but depending on the key operation, various further service routines such as the previously stored blood sugar value output can be started to perform various functions.

In addition, the apparatus of the present invention is provided with a display device 2 for expressing visual information and a buzzer BZ for audibly notifying each operation state.

Next, the present invention will be described in detail with reference to the detailed circuit diagram of FIG. 2 as a specific embodiment of FIG.

In FIG. 2, the clock generator 5 is for providing a clock pulse for use in the microcomputer 1, and the power supply 4 composed of the transistor Q1 and the plurality of resistors R1 and R2 and the battery is a microcomputer. (1) In addition, it is configured to supply a power supply (VDD) and a + 6V power supply to each element of the circuit. In particular, the LCD power supply 3 obtains a voltage to be decompressed from the diodes D5 to D10 connected in series, and supplies the necessary power to the LCD which is the display device 2. Then, the buzzer BZ connected to the microcomputer 1 is installed to give a sound suitable for each situation as a sound to the user. In the circuit of FIG. 2, block "6" is a battery voltage control part, and block "7" is a reset setting part.

When the user turns on the power key SW2, the microcomputer 1 displays "0" on the display device 2 and informs the user that the measurement standby state.

At this time, the blood glucose meter of the present invention performs an automatic zero operation, which is intended to increase measurement accuracy. The blood sugar strip S, which is discolored differently according to the concentration of sugar contained in the blood, before the LED 8 and the photodiode 9, which are cut off from the external environment, are inserted into the paired sensor unit 22, that is, the blood sugar The above auto zero operation is executed before the measurement operation of.

In FIG. 2, the light emitted from the LED 8 changes according to the width of the pulse output by the microcomputer 1 through its output port O1, and the photodiode 9 receives the light received from the LED 8. As a result, a corresponding current is output. The microcomputer 1 has a range of output voltages corresponding to the color of the strip S as data composed of a lower limit and an upper limit, and also has a reference value that is halfway between the upper limit and the lower limit. The above reference value is used in the auto zero operation.

The microcomputer 1 outputs a pulse signal having a narrow pulse width through the output port O1 so that the light intensity is lower than the reference value close to the lower limit at first, and the resistors R18 to R20 and the capacitors C5 and C6 are output. When the above-mentioned pulse signal is integrated through the integrated circuit 10, it is amplified by the amplifier 11 and output as a constant voltage. Therefore, the magnitude of this voltage is proportional to the pulse width of the microcomputer 1.

When the switching transistor Q2 of the light emitting unit 12 is turned on / off according to the output of the amplifier 11, the LED 8 emits light darker than the corresponding reference value, and is coupled to the LED 8 in pairs. The corresponding current is detected by the photodiode 9 thus obtained.

The current is input to the first input port I1 of the microcomputer 1 by the first amplifier stage 13 constituted by the OP amplifiers OP1 and OP2 as a signal of 1/2 magnitude of the I2 port voltage. The second amplifier stage 14 constituted by the OP amplifier OP3 detects twice the voltage of the I1 port input and inputs it to the second input port I2 of the microcomputer 1. The microcomputer 1 stores a value for the voltage value input through the input ports I1 and I2.

Next, the microcomputer 1 sends an output pulse corresponding to the light intensity higher than the reference value close to the upper limit through the output port O1 as in the above operation, and stores the detected voltage value according to the above process.

The microcomputer 1 is well known to output the correct LED light corresponding to the reference voltage from the stored value. The pulse width is determined from the proportional arithmetic expression and finally output through the output port O1 so that the intensity of the light can match the reference value. After that, close the auto zero operation.

In this case, the voltage input to the input ports I1 and I2 is converted into digital data by an A / D converter (not shown) built in the microcomputer 1 and used as data. In FIG. 2, the circuit block 15 is provided to provide a reference voltage during A / D conversion.

In this state in which the auto zero operation is completed and prepared, the microcomputer 1 waits for the start key SW1 to be turned on through the kiss can.

The user prepares the collected blood, presses the start key SW1, and drops the blood on the prepared strip S to wait for the color to change. At this time, the microcomputer 1 shows the count value inverted by the timer on the display device 2 so as to inform the extent thereof. This can typically be 60 seconds or 120 seconds.

According to an embodiment of the present invention, the user wipes the blood on the strip S and wipes off the residual blood on the strip S at a point where the count value is 23 or 63 seconds. At this time, the microcomputer 1 informs the remaining blood removal point through the buzzer BZ. In the case of 23 seconds or 63 seconds, 63 seconds is 120 seconds, which depends on the characteristics of the strip S used.

As described above, at the time of displaying the display device 2 for 13 seconds after removing residual blood, the microcomputer 1 informs the insertion point of the strip S together with the buzzer sound. The above operation is the operation of the normal mode, and in the fast mode, the start key SW1 is pressed during the count reduction so as to be output by inserting the strip S. FIG.

In the normal mode, the user inserts the discolored strip S into the sensor unit 22 between the LED 8 and the photodiode 9 after 13 seconds. Just do it. In this interpolation measurement, the light generally emitted from the LED 8 and reflected by the strip S is transmitted to the photodiode 9 so that the LED 8 and the photodiode 9 can be It is not arranged in a straight line, but arranged slightly shifted, and a strip S is placed therebetween. For this reason, a reflector is placed so that the reflected light can be used in the auto zero operation before the strip S is inserted.

The intensity of light received by the photodiode 9 from the discolored strip S is different. As the blood glucose is higher, the strip S becomes darker and the intensity of the reflected light becomes weaker, so that the measurement current is weak. This suggests that there is a relationship between the blood glucose level and the output voltage, and the applicant has conducted a number of experiments using the blood glucose meter. As shown in FIG. 3, the blood glucose level (mg / dl) (or [mmol / l] unit) is shown in FIG. ) And the voltage [0 to 5 V] from this apparatus have a non-linear relationship, and thus a microcomputer ROM table is provided.

Although not shown inside the microcomputer 1, a ROM including a ROM table and a program for operating a device, a RAM for storing data, and a sensor voltage input to the input ports I1 and I2 are 2; Each A / D converter is stored in RAM and then processed.

The detected voltage from the sensor consists of the sensor voltage obtained from the first amplifier 13 and twice the voltage of the output of the first amplifier obtained from the second amplifier 14, each of which is digital by two A / D converters. Converted to data. The procedure for finding blood glucose level using these two data is as follows.

Since the output of the second amplifier 14 is the sensor voltage for the voltage range I to 0 to 2.5V in FIG. 3, the output of the second amplifier 14 is used as data by having a resolution of 2 ⁸ in the 8-bit A / D converter in the program. . However, since the sensor output is also output at 2.5V or more when viewed from the second input port I2, the first output is to provide a resolution of about 2 ⁸ resolution for the second section II, that is, the 2.5V to 5V signal. The output of the first amplifier 2 input to the input port I1 is utilized, and the processing is doubled on the program. When a sensor voltage of 2.5V or more is input, the internal program detects the first input port I1 and accepts the sensor voltage A / D conversion instead of detecting the second input port. This means that if the program doubles the input voltage of the first port and is 2.5V or more, the first port is detected, and the blood sugar value is found and output with 2 ⁸ resolutions to the first port voltage. This is useful if you want to get more than 256 resolutions with an 8-bit A / D converter. In FIG. 3, the blood glucose level of section B is referred to the first section I, and the blood glucose level of section A is referred to the second section II.

The measuring method depending on the apparatus of the present invention can be understood from the simplified flowchart shown in FIG. This operation flow follows the operation process described above, and therefore only a schematic process will be described.

First, steps 1 and 2 are routines to initialize the device when the battery is inserted and check that the power key is on. When the power key is turned on in step 2, the device initiates an autozero operation as described earlier to precisely match the light intensity of the light emitting diode corresponding to the prepared sensor detection reference voltage. This is to minimize measurement errors and to compensate for changes in the sensor's surroundings that can be varied. In this manner, since the auto zero operation is in the measurement standby state, the display device displays a number of "0".

At this time, when the user collects the blood and presses the start key (SW1), the timer is started, the blood is buried on the strip, the timer number is subtracted, and the normal mode measurement step is performed as in step 6. Wait for the buzzer to sound at 23 or 60 seconds. After that, it is subtracted again to indicate that the strip is inserted at 13 seconds and proceeds to step 7 when it reaches zero. In this case, the fast measurement mode is the case where step 6 is YES and goes straight to step 7.

In the normal measurement mode, when the time of the timer becomes " 0 " (with the discolored strip placed in the sensor section), the microcomputer 1 turns on the light emitting element. Light irradiated from the light emitting device is reflected by the inserted strip to detect an output value corresponding to the light intensity applied to the photodiode. Referring to the ROM table according to the above-described procedure using the detected sensor voltage data as in step 7, the data obtained from the ROM table is the blood sugar level, so the blood sugar value may be displayed on the display unit as shown in step 8. The displayed blood glucose value is stored in the built-in memory and returns to the measurement standby state.

As described above, in the embodiment of the present invention, the user can easily measure the blood glucose level, and is easy to carry, and at the same time, a high-precision measurement value can be calculated by correcting the error of the ambient light amount or the electronic component through the auto zero function. It is possible to provide an automatic blood glucose apparatus having an auto zero function and a measuring method thereof having an effect of being able to be effective.

Claims (3)

It includes a memory having a reference value stored therein, and adjusts the pulse width of the pulse signal for emitting light to emit light so that the current corresponding to the reference value can be detected through the reflected light at the beginning of operation After the zero operation, the microcomputer 1 outputs a control signal for calculating and displaying a blood sugar value according to the intensity of light measured from the reflected light by the discolored strip, and the pulse signal input from the microcomputer 1 described above. Reflected by a pulse-voltage converter 20 for outputting a DC voltage corresponding to the light-emitting means for emitting light corresponding to the output of the pulse-voltage converter 20, and a discolored strip by blood. A sensor unit 22 having means for receiving light and generating a current corresponding thereto, and receiving a current signal from the sensor unit 22 and receiving a detection signal corresponding thereto. The blood glucose value corresponding to the data value obtained by converting the sensor signal detection unit 21 and the detection signal of the sensor signal detection unit 21 to the digital value from the ROM table built in the microcomputer 1 to display the blood glucose value. An automatic blood glucose measurement apparatus having an auto zero function, characterized in that it comprises a display device (2). The pulse voltage converter of claim 1, wherein the pulse-voltage converter includes a resistor that receives and integrates a pulse having a predetermined pulse width, an integrator of a capacitor configuration, and an amplifier that amplifies the integrated signal in proportion to the pulse width. Automatic blood glucose measurement apparatus having an auto zero function, characterized in that. 2. The sensor of claim 1, wherein the sensor signal detecting unit has a first amplifying means for outputting a sensor voltage and a second amplifying means for amplifying twice the output of the first amplifying means, each of which is analog-digital. Automatic blood glucose measurement device having an auto zero function, characterized in that the input to the transducer.