JPS6036009B2 - electronic thermometer - Google Patents

Description

[Detailed description of the invention]

The recent trend toward electrification of body measurement devices has shifted to the health management field. Electronic pulse timers, high power sound amplifiers to sense the fetal heart, and electronic temperature sensors have become common knowledge. One such electronic temperature sensor is disclosed in U.S. Pat. This device quickly measures the temperature of a patient. Although many of these conventional devices utilize counting technology, each component and circuit element cannot satisfy both high speed and miniaturization. Most often, when designing and fabricating these into fairly complex health electronic circuits, it has been necessary to use discrete components and logic elements. Due to size limitations, it has not always been possible to include a desired number of functional bodies in one package. Accordingly, it is an object of the present invention to provide an improved temperature sensor that utilizes counting techniques. Another object of the present invention is to provide an improved temperature sensor that senses temperature over a short period of time and provides an output in either Celsius or Fahrenheit. Yet another object of the present invention is to provide an improved temperature sensor that utilizes inexpensive thermistors and readily available electronic components. The present invention uses two measurements to predict the final temperature.
To provide an electronic device for use in an electronic thermometer that requires only one operation. INDUSTRIAL APPLICATION This invention is used for diagnostic temperature measurement, and is used for thermistor type probe inserted into a patient's body. Electronic thermometers use an equation based on the response curve of a typical thermistor bead or element. This equation requires that the two measurements be taken at specific times and, just as importantly, at critical fixed times. This information provides equipment implementing this equation with the ability to measure temperature on both Fahrenheit and Celsius scales. It also provides an apparatus for indicating low battery voltage conditions and, more importantly, discloses a specialized counting logic circuit that performs operations in an optimal manner. Additionally, the present invention counts and displays the patient's final temperature. Use readily available electronic devices. The present invention
The following components are: (i) a temperature measuring device having a temperature response element with a temperature one-hour response curve expressed by the following equation, [where T
P is the final temperature to be measured, T is the measured temperature at the first time, T2 is the measured temperature at the second time after the first time, Δt is the difference between the first time and the second time. ↑ is the thermal time constant that varies depending on the temperature response element, and e represents the base of the natural logarithm]: A device that converts a temperature measurement value into a pulse signal with a pulse line return number corresponding to the measured temperature; ( iii- a counter device that counts the pulses from the converter and provides an output signal representative of the estimated final temperature;
A device that connects to this counter device and visually displays the estimated final temperature in digital form; A device for generating a pulse signal corresponding to a conversion device from a converting device and controlling the operation of a counter device, the device comprising: a crystal oscillator device that generates pulses at a predetermined repetition rate; A counter device that connects to the device and generates an output signal at predetermined intervals, and a counter device that is connected to the device and generates an output signal at predetermined intervals
connected to the Hayabusa counter, and also connected to the conversion device and the counter device, so that the conversion device generates a pulse signal for an arbitrary period at the first predetermined time and counts in one direction. said counter device is set, and said counter device is set to cause a pulse signal to be generated from said converting device for an arbitrary period of time at said second predetermined time to count in the opposite direction, thereby said counter device a control device comprising a plurality of logic gate devices whose outputs can be changed from (2r2-T,); An on/off type switch device for displaying the temperature on a display device. The present invention will be specifically described below with reference to the accompanying drawings. FIG. 1 shows a typical response curve for a commercially available thermistor type temperature sensor. The vertical axis T represents temperature, and the horizontal axis t represents time. The actual response curve does not necessarily have to be exactly a true exponential curve, but it is generally assumed to be an exponential curve. Since the purpose of the present invention is to allow the use of relatively inexpensive and readily available thermistors, these thermistors may not be capable of accurate measurement over a wide range of temperatures. Therefore, the response of the thermistor does not fall below a value called the resting response denoted by TR, and similarly this response is
The true final temperature shown by is definitely not reached, but only very close to it. As shown in FIG. 1, the time of the static response temperature TR is t. o, the first measured temperature at the first time t, is denoted by T, and the second measured temperature at the second time t2 is denoted by T2. Number 1 in Figure 1
The response curve indicated by 0 is an exponential curve, and the temperature T on the response curve at any time t is expressed by the following equation:

[1}'Thus, it is given. T=TR+(TF-TR)(11e-t/↑) tl
'However, TR and TF are as defined above,
↑ is a thermal time constant that varies depending on the temperature responsive element. By substituting the measured temperature T during the first time period and the measured temperature T2 during the second time period into the above equation, and finding the final temperature TF from these substitution formulas, the following equation is obtained.
It can be grown. If the time difference (beat t,) between the first time t, and the second time t2 is expressed by ΔT, the following arithmetic expression {3' can be obtained from the above equation (2). The purpose of the present invention is to obtain the final temperature TF in the simplest way possible without waiting for the temperature measuring device to stabilize (unlimited approach to TF), so the above calculation formula (3
' should also be solved in the simplest way to find the TF value. In order to solve the above equation (3) in the simplest form, we can choose e23,000.5. That is, eji=. ・5 '4) By using the value of ■ in this equation The above self-operating formula '3' is TF=2r2-T, '5}
It can be expressed as Rewriting equation (4} gives △t [6, e2f, and calculating △t from this gives △t=ra−t,=↑ln2 [7}. The typical value of ↑ is that of a normal thermistor. The value of the natural logarithm of 2 (ln2) and the above 1
Substituting 9 seconds into the equation, △t = 19 sand x 0.693 is also 1
Nail @ ■Can be removed. This means that the invention requires only a 13 second delay between the first temperature measurement T, and the second temperature measurement n2. Since the present invention is intended to be highly practical, when inserting a thermistor collection needle into a patient, it is necessary to take into account that the body tissue surrounding the collection needle will be momentarily cooled by the low temperature of the grandchild needle. I found out something. For this purpose, the first temperature T,
It is better to delay the measurement time. If Δt is equal to 13 seconds as above, a convenient delay time is 10,000 seconds. In other words, the operation cycle is 3 sand (10,000 seconds, 11 mirror sand)
It is preferable to Next, FIG. 2 shows an embodiment of the present invention. This is shown in the diagram. 2 shows the corresponding resistance changes of the thermistor's output wires 22, 24 and 26 connected to the Celsius/Fahrenheit (C/F) selection unit 28 of a thermistor inserted into the patient's body. This C/F selection unit 28
A temperature/frequency analog-to-digital (A/D) converter 30' is electrically connected as shown in detail in the figure. This A/○ converter 30 operates and converts the analog voltage related to the temperature obtained by the resistance change into the pulse line return number (
That is, it is converted into a digital signal having temperature information expressed as frequency). The center of the A/D converter 30 is an oscillator whose vibration period is controlled by the resistance of a thermistor provided in the sampling needle 20. A digital signal containing pulse repetition rate temperature information is then sent over line 32 to a conventional up/down counter 34. This IG falcon counter 34 is cleared or reset each time the unit is used, for example by a signal on line 36 from the power switch 38, when the power switch 38 is actuated. The aspect of this up/down IG Hayabusa counter 34 is as follows:
The line 40' generated by the gate logic unit 42 is controlled by the up/down command signal 40'. This gate logic unit 42 is shown in detail in FIG. Since the invention relies on equation {1) to obtain an approximation of temperature, the time between two temperature measurements (Δt) must be controlled. The temperature to frequency converter is enabled a selected number of times by a signal appearing on line 44 produced by gate logic unit 42. Extrapolating from the inventor's above-mentioned co-pending application, the final temperature reached is equal to twice the second temperature measurement (L) minus the first temperature measurement (T,).
Of course, since T occurs first to subtract it, counter 34 is first set to count down by the line 401 commands. Gate logic unit 42 then generates an enable signal on line 44 and T, is input to counter 34 via line 32. In order to input a value twice the value of T2, and since the temperature is represented by a continuous pulse flow, the line 32 is input for a time twice the time during which T is input.
It is only necessary to input a certain signal to the counter 34. The time required to obtain good results is 1 second for T, and 2 seconds for T2. Therefore, if the signal on line 44 enables converter 30 for two seconds, counter 34 must be incremented by command of the four-way control signal on line 44. Therefore, the counter 34
It includes a number of pulses representing twice the temperature measurement minus the first temperature measurement. The contents of counter 34 are then sent in parallel to a conventional buffer storage unit 46 and then to multiplexer 48. This multiplexer 48 is connected to a light emitting diode (LED) indicator 5 in a manner well known in the art.
serves to reduce the amount of power required to drive 0.
Once decoded by a conventional decoder 52, the contents of the counter are displayed by an LED display 50. Oscillator 54 and digit selector 56 serve as a predetermined display driver and are connected to multiplexer 48 via line 58. Counter 34, buffer 46, multiplexer 48,
Decoder 52, oscillator 54 and digit selector 5
6 is commercially available and is in a simple integrated circuit package, indicated by dashed line 60. It is well known how to connect these functional units in order to receive pulse signals and display the information contained in these pulse signals.
Since the embodiment of the present invention measures the body temperature of a human body, the display must be able to display a number greater than 99. However, in a display with hundreds of digits, it is only necessary to display 1, power management is important, and it is not desirable to display the temperature as "098.6", so the present invention
Provides a device that blanks out 100 digits if it is not displayed. Over one hundred indicator 62 is connected to the most significant digit signal on line 64 from decoder 66 and to line 58 from digit selector 56. This over-one-hundred indicator 62 is simply a logic gate that generates an enable signal on line 66, enabling the hundred digits only when they are needed to display a 1 and disabling them so that they do not display a 0. . In order to eliminate the possibility of misreading due to insufficient voltage, a low storage battery indicator 68 is provided. This battery indicator 68 is a comparator that compares the internal bias voltage V on line 70 to a constant voltage drop across a diode or the like. This accumulator indicator has its input connected to the output of the display drive unit on line 72 and its output line 74 as L.
It is connected to all decimal points of the ED display 50.
Upon detecting that the voltage on line 70 has dropped below a certain level, the display driver switches on line 72, indicator 68 and line 7.
4 to all IG focal points of the display 50, which are continuously illuminated to alert the operator that the battery voltage is below a minimum level. In this example, it is desirable to complete the measurement prediction function within 3 days, and as already explained, it is desirable to complete the measurement prediction function within 3 days.
It is necessary to know the exact time when each temperature measurement is taken. Therefore, an accurate timing device must be provided. 20 per second
A crystal controlled oscillator or clock 76 is provided which generates a signal on line 77 having a frequency of 97152 pulses. This 2097152 Hertz signal is sent to a 21 stage binary divider 78 to generate an accurate 1.0 second clock pulse train. This pulse train is then sent via line 79 to a group of IG Hayabusa counters 80'. Details of this counter are shown in FIG. These IG Hayabusa counters 8 and 82 are connected via a double track, and counter 34
is canceled by the same signal on line 36 used to cancel . Clock 76' IG Hayabusa counter 80 and gate logic unit 42 act together to provide the necessary internal timing to enable temperature-to-frequency analog-to-digital converter 30 to generate a line that actually contains the predicted temperature value. 32
generates a signal. Gate logic unit 42, shown in detail in FIG. 4, provides up and down commands on line 4 to counter 34 as well as a power off command on line 84 which is sent to power switch 38. This command is to conserve the storage battery 86 by performing fogging or disconnection after a certain period of time has elapsed. Kasumimoto Shinya's acceptance time is said to be 4 seconds. Gate logic unit 42 is also used to control display on/off switch 88. This switch connects the line 90 to the LED display recorder 52.
Generates one available signal. This enable signal provides a blanking pulse to decoder 52 so that the display does not show a temperature increase, but instead only shows the final predicted temperature. Gate logic unit 42, IG Hayabusa counter 80 and crystal control clock 76 also generate timing signals at predetermined intervals. For example, a signal is generated on the line 92 after 19 sand has passed, and another signal is generated on the line 94 after 3 inkstone sand has passed. These signals are connected to indicate lights or buzzers used for pulsing or other tasks that require precise timing. Next, FIG. 3 shows in detail the pointer, the Celsius/Fahrenheit selector, and the temperature/frequency analog/digital converter. Sun needle 20 includes a single thermistor element or bead 100 and has one direct output lead 22 . The other output lead 11 of this thermistor is connected to two variable resistors 112 and 114 which serve to calibrate the thermistor 100. These variable resistors are necessary because thermistors are used for two separate temperature scales. Celsius/Fahrenheit selector 28 comprises a manual three-pole dual-role switch 116. The A/D converter 30 is actually an oscillator whose vibrational variables vary by R and C, in this case the resistance being varied. Conventional operational amplifiers 120 are connected in a well-known manner to form a free-running multipipulator, except that the thermistor grandchild 20 is inserted in the return path. Therefore, the vibration frequency or pulse repetition rate is 100
It changes depending on the temperature sensed by. Furthermore,
Because the present invention generates a signal with multiple pulses representing temperature on one of two different scales, amplifier 120 must oscillate at two different rates. To do this, two variable resistors 112 and 11 in the feedback path are used.
In addition to 4, two isolation capacitors 22 and 124 are connected to amplifier 120' via selector switch 116. Converter 30 of FIG. 2 is enabled, ie, operational amplifier 120 is caused to oscillate by the enable signal appearing on line 44. As previously mentioned, this signal is generated by gate logic unit 42 and is set to 1 at certain times.
The oscillator is turned on for a second, and then again at a certain time for two seconds. The output of the oscillator is sent through a conventional amplifier 126 before being sent via line 32 to the up/down counter 34 of FIG. Next, FIG. 4 shows the 1G Hayabusa counter and gate logic unit in detail. 20 on line 77 from crystal control clock 76 in FIG.
The 97152 Hertz signal produces counts in 1.0 second increments, ie, produces a signal on line 78 every 1.0 second. This signal is sent to a one-shot counter 144 which counts at one second intervals and generates an overflow signal on line 146 for every one sand. The clock signal then receives the final I
Sent to G Hayabusa Counter 148, this Counter is 1st Dan.
Count in intervals. 1bo Hayabusa counter 144 and 148 and 2
Lead divider 78 is reset by a reset signal on line 36 from the power switch. However, this reset signal occurs on the 1G Hayabusa counter because the power switch is rendered non-conductive after 4 cycles, as described above. IG Hayabusa counter 48 is tapped to the fourth tap, and this signal is sent by line 150 to AND gate 1 52, which forms part of the gate logic unit. The second input to this AND gate 152 is the bias voltage VQ, and when both signals are present, a signal is generated on line 84 when the power is turned off. As previously mentioned, the enable signal must be present at the temperature to frequency converter for 1 second after 15 minutes and 2 seconds after 3 minutes. These enable signals appear on line 44 and are sent to temperature-to-frequency converter 30' of FIG. 2, where they are generated by three-input AND gate 154. Furthermore, there are three AND gates 1 56 , 1 5 8 and 160 whose outputs are connected to AND gate 154 . These AND gates 156, 158 and 160 have as inputs various output taps from IG Hayabusa counters 144 and 148. These output taps are selected in a known manner to produce output signals on line 44 at 19 seconds, 3 seconds, and 31 seconds. Since the enable signal must be present for 2 seconds after 3 seconds, it is necessary to generate the enable signal at 31 seconds. A dual flip-flop device 1 is used to obtain auxiliary timing signals on lines 92 and 94.
62 is provided. As previously mentioned, after 15 seconds a signal will be present on line 92, so to accomplish this AND gates 16
The signal on line 164 generated by 6 sets one of the flip-flops. This AND gate 166 has 15
It is connected to the IQ Hayabusa counter 44, 146 so that an output signal is obtained after seconds have elapsed. Similarly, the second half of dual flip-flop 162 is set directly by the signal from 1G Hayabusa counter 148, which counts in 1 sand intervals after 3M sands. It is sent to the up/down 1G ship counter in Figure 2 via this 3 sand signal or line 40,
Works as an up/down command signal. That is, according to the present invention, it is necessary to add and count the second temperature measurement (T2) after three cycles, and the signal on line 40 is this predetermined command. It should be noted that the above-mentioned embodiments are merely illustrative. Any type of thermistor probe may be used, as well as various other logic elements and counters. Accordingly, the invention is not to be considered limited to the illustrated embodiments, except as described in the claims below.

[Brief explanation of drawings]

Figure 1 is a temperature response characteristic curve of a typical thermistor type temperature sensor, Figure 2 is a block diagram showing an embodiment of the temperature sensing unit according to the present invention, and Figure 3 is used in the device shown in Figure 2. Schematic diagram of Celsius/Fahrenheit selector unit, No. 4
2 is a logic diagram of a gated logic unit shown in the apparatus of FIG. 2; FIG. 10...Response curve, 20...Thermistor needle measurement, 28
．． ．． ．． Celsius/Fahrenheit selection unit, 30...analog
Digital converter, 34... Up/down IG Hayabusa counter, 38... Power switch, 42... Gate logic unit, 46... Buffer storage device, 48...
Multiplexer, 50... Light emitting diode display, 5
2, 66...decoder, 54...oscillator, 56...
・Digital selector, 62...Over one hundred display, 80,144...1G Hayabusa counter, 86
...Storage battery, 100...Thermistor, 116...
Three-pole switch, 120, 126...Amplifier, 152, 15
4,156,158,160...AND gate, 162...
Flippf. Tsupu. F/G. ” F/G. 2 F/G. 3 F/G. 4

Claims (1)

[Claims] First-order components, namely: (i) A temperature measuring device having a temperature-responsive element with a temperature-time response curve expressed by the following calculation formula, ▲ includes mathematical formulas, chemical formulas, tables, etc. ▼ [Here, T_F is the final temperature to be measured, T_1 is the measured temperature at the first time, T_2 is the measured temperature at the second time after the first time, and Δt is the difference between the first time and the second time. the time difference between the time of
(2) is a thermal time constant that varies depending on the temperature response element, and e is the base of the natural logarithm]; (ii) A device that converts a temperature measurement value into a pulse signal with a pulse repetition rate corresponding to the measured temperature;
(iii) a counter device that counts the pulses from this converter and provides an output signal representing the estimated final temperature; (iv)
(v) a device connected to said counter device for digitally and visually displaying the estimated final temperature; (v) a measured temperature for any period of time at a first predetermined time and for any period of time at a second predetermined time; A device for generating a pulse signal corresponding to a pulse signal from a converting device and controlling the operation of a counter device, the device comprising: (a) a crystal oscillator device that generates pulses at a predetermined repetition rate; and (b) this oscillator. (c) a decimal counter device connected to the decimal counter device and generating an output signal at predetermined time intervals; The counter device is set to generate a pulse signal for an arbitrary period at a predetermined time from the converter and count in one direction, and convert the pulse signal for an arbitrary period at the second predetermined time. Said counter device is set to count in the opposite direction from the counter device, thereby causing (2)
and (vi) a control device comprising a plurality of logic gate devices adapted to provide an output corresponding to T_2-T_1); and (vi) a control device comprising a plurality of logic gate devices so as to obtain an output corresponding to T_2-T_1); Turn on/off to display temperature on device
An electronic thermometer that indicates an estimated final temperature, characterized in that it is comprised of an off-type switch device; 2. Claim 1, comprising a device connected to the temperature measuring device that converts and controls the pulse repetition rate to display the measured temperature in either Fahrenheit units, Celsius units, or Celsius units. Electronic thermometer as described. 3. A circuit device connected to the counter device and to the display device for selectively disabling the most significant digit of the visual display when the counting device contains a number below a certain level. An electronic thermometer according to item 1 or 2 of the range. 4. Claims comprising a power source and a power switch device electrically connected to the power source and electrically connected to the plurality of logic gate devices to disable the power source upon generation of a signal from the gate device. The electronic thermometer according to any one of Items 1 to 3. 5. A voltage level indicator as claimed in any one of claims 1 to 4, comprising a voltage level indicator connected to the power supply and to the visual display device for illuminating the display by generating a constant voltage level. electronic thermometer. 6. The electronic thermometer of claim 1, wherein said crystal oscillator device comprises a binary divider for dividing the oscillator signal into a pulse signal having pulses occurring every second. 7. The device according to any one of claims 2 to 6, wherein the device for controlling the pulse repetition rate, in which the temperature to be measured is in either Fahrenheit units or Celsius units, comprises a plurality of variable resistors. Electronic thermometer. 8. The electronic thermometer according to any one of claims 1 to 7, wherein the constant level corresponds to 100 degrees Fahrenheit. 9. Claims 6 to 9, comprising a binary divider electrically connected between the crystal oscillator device and the decimal counter device for dividing the oscillator output signal into a pulse signal having pulses occurring every second. The electronic thermometer according to any one of Item 8. 10 pulses before the output signal is generated by the plurality of logic gate devices are 15 pulses, 30 pulses,
Claim 7 including 31 pulses and 40 pulses
The electronic thermometer according to any one of Items 1 to 9. 11 A patent comprising a power source and a power switch device electrically connected to the power source and electrically connected to the plurality of logic gate devices to disable the power source by generating the output signal after the pulse. The electronic thermometer according to claim 10. 12. The conversion device includes an oscillator whose frequency is controlled by the temperature-responsive element, and the control device includes a selective electrical element and a switch device for displaying in either Fahrenheit or Celsius units. 12. Selective electrical coupling of said selective electrical element to an oscillator causes the oscillator to oscillate in selective modes and to be expressed in either Fahrenheit or Celsius units. The electronic thermometer according to any one of the items. 13. The electronic thermometer of claim 12, wherein the device for measuring temperature includes a sampling needle containing the temperature responsive element, and several of the selective electric elements are disposed within the sampling needle. 14. The control device includes a device for generating at least one timing signal, thereby causing the at least one
Claims 1 to 1 that use two timing signals to perform a function that requires accurate timing.
The electronic thermometer according to any one of Item 3. 15. The electronic thermometer of claim 14, wherein the device for generating at least one timing signal includes a device for generating at least one timing signal after at least one fixed time period. 16 The above-mentioned at least one certain period of time is 1
16. An electronic thermometer according to claim 14 or 15, including a time period of 5 seconds. 17 The at least one fixed period of time is 3
The electronic thermometer according to claim 14 or 15, which includes 0 seconds.