JP2010513911A - Apparatus and method for measuring core temperature - Google Patents

Abstract

  The present invention provides an apparatus for determining the core temperature of an object such as a human body. Thereby, the device has a heat flux between the first side and the second side at the position of the first and second sides and the respective first and second temperature sensors and the second tail temperature sensor. A modulation means for lowering the temperature of the second sensor by changing. The modulation means can lower the temperature by controlling the heat flux, not by adding heat, but by controlling the heat flux, which inherently makes the device safe and often consumes less power .

Description

  The present invention relates to measuring the core temperature of an object.

  Specifically, in a first aspect, the invention includes a structure having a first side to be positioned with respect to an object and a second side substantially opposite the first side, A temperature sensor is positioned and arranged to measure the temperature on the first side, and a second temperature sensor is positioned and arranged to measure the temperature on the second side to measure the core temperature of the object. Relates to a device for

  In a second aspect, the present invention provides a structure having a first temperature sensor at a position for measuring a surface temperature of an object, a second temperature sensor, and a first side and a second side. Positioning the structure between the first temperature sensor and the second temperature sensor with the sensor on the first side and the second temperature sensor on the second side, a first comprising the first temperature sensor Measuring the first temperature value on the side, measuring the first temperature value on the second side with the second temperature sensor, measuring the second temperature with the first temperature sensor, and measuring the second temperature with the second temperature sensor It relates to a method for measuring a core temperature of an object comprising measuring and calculating a core temperature from each of a first temperature and a second temperature.

  Document US Pat. No. 6,886,978 discloses a first temperature sensor and a second temperature sensor, a heat insulating member disposed between the first temperature sensor and the second temperature sensor, and a heater for heating a living body. The first sensor measures the temperature in the vicinity of the heater, and the second temperature sensor measures the temperature inside the living body, measuring the temperature at a position on the living body opposite to the heater across the insulating member. A thermometer is disclosed.

  The known device and the corresponding method have the disadvantage that it has the risk of overheating or burning the organism, which is undesirable.

  It is an object of the present invention to provide an apparatus that is safe for measuring temperature, particularly for living organisms, and in a second aspect to provide such a method.

  The above objective is accomplished according to the present invention using a device for measuring the core temperature of an object of the type described above, which device is located between the first side and the second side at the position of the second temperature sensor. Modulation means for reducing the temperature of the second sensor by changing the heat flux of the second sensor.

  The device according to the invention is safer than known devices. The known devices described above also operate according to the principle of measuring the temperature of the dual sensor structure at different heat fluxes in order to obtain the core temperature, but use heating to build up such different heat fluxes. First, the normal surface temperature of a living body is between about 25 ° C. and at most about 40 ° C., but pain is perceived at a temperature as low as 45 ° C. Such temperatures are experienced by living organisms if the insulation fails or the position of the device is inadvertently reversed. In addition, the danger zone begins at a temperature of about 45-50 ° C. This means that for known devices there is only a very small safe temperature window, which leads to noisy measurements and long measurement times.

  Conversely, the present invention achieves the goal of changing the heat flux through modulation means that can achieve lower temperatures. This is achieved, for example, by affecting heat transport instead of generating heat as in conventional value techniques. Note, for example, temperatures down to a few degrees C do not cause problems for living organisms, at least for the small surfaces that are measured. This means that temperature differences of up to 30-40 ° C. can be achieved, which reduces measurement noise and allows more accurate measurements. This is because the time derivative of temperature is often larger and there is still no need for strong thermal coupling (high thermal conductivity).

  An important advantage of the present invention is that it allows for lower power designs, as will be further elucidated below.

  In this context, when the temperature of the second temperature sensor is meant, this is at the location where the second temperature sensor is present or at the part of the second side in the vicinity or at that part of the side associated with the heat flux. It should be understood to mean temperature.

  Moreover, if the heat flux is significant, i.e. changed by at least 10%, it is preferable to increase the measurement accuracy, but smaller changes are not excluded.

  Furthermore, the first side is the side that is to be positioned relative to the object, i.e. to be applied or placed in sufficient thermal coupling with it for the temperature to be measured. In some cases, a symmetric design is possible, as discussed below. In that case, the first and second sides are interchangeable. In other asymmetric cases, the first side and the second side may be recognizable to those skilled in the art.

  Moreover, the first temperature sensor does not have to be fixed on the first side, but moves relative to that side as long as the sensor can be positioned between the object to be measured and the first side. It may be possible. In a preferred case, the first temperature sensor is fixed on the first side or even embedded in the first side. Similarly, the second temperature sensor is preferably fixed on the second side, or even embedded in the second side, but this need not be the case.

  As a general note, an object whose core temperature can be measured is not limited to a living body such as a human body. They can also be containers with specific contents such as, for example, infant (heated) milk bottles or containers with dangerous contents such as chemicals in the processing environment.

  Specifically, the modulating means is arranged to switch between a first heat flux state and a second heat flux state, and the energy consumption of the device in its steady state is substantially unchanged. This reflects the advantage that the modulation means does not have to generate heat to affect the heat flux, which not only reduces power consumption but also prevents the risk of overheating.

  Preferably, the steady state energy consumption is substantially zero for both the first and second heat flux conditions. In this particular embodiment, in principle, the lowest steady state energy consumption can be achieved. This is because changes in the passive characteristics of the device are used to affect the heat flux. For the purposes of the present invention, a substantially zero energy consumption means substantially no heating. Other consumptions of energy are not considered here for purposes of measurement, calculation, etc. It will be apparent that a very long service life can be achieved by adding a simple power source, such as a battery, to power the accompanying energy consumption for measurements, calculations, etc. Thus, in an advantageous embodiment, the device is cordless and includes an energy source, preferably a battery. However, it should be noted that the absence of energy consumption modulation means is not strictly necessary to obtain at least some of the benefits such as temperature safety. The modulation means may be arranged to reduce the temperature to a temperature below that achievable by the device when the device measures the core temperature of the object without consuming any power. The known devices described above are not intended, but themselves allow for a temperature drop by starting with a measurement using an active heater and then performing the measurement with the heater turned off. However, temperatures below the equilibrium temperature in the latter situation are not achievable and the risk of higher temperatures remains the same. In contrast, the present invention, as will become apparent from the following, in the absence of any external supply of energy to the device (apart from thermal energy from objects or surroundings not meant for external energy for this purpose). , It is always possible to lower the temperature below the equilibrium temperature. One can also state that known devices cannot actively lower the temperature by performing their function. Because it can only add heat and thus increase the temperature. The device can actively lower the temperature by switching from a first heat flux state (eg, a well-isolated state) to a second state. For now, it is enough to say that actively lowering the temperature is safer than raising the temperature.

  Specifically, the thermal coupling between the first side, the second side and the surrounding first and the first side, the second side and the other surrounding is variable. In this embodiment, the heat flux is affected by the way it is coupled to other parts of the device.

  Advantageously, the structure has a thermal conductivity that is at least locally variable. In other words, the thermal conductivity between the first and the sensor or at least between the respective first and second side portions at or near the position of the respective temperature sensor is variable. The modulating means may include this structure or may be part of this structure. Local variability ensures the possibility of two different measurements of the surface temperature of the object, which allows the calculation of the core temperature according to techniques known per se, which will be further elucidated below.

  The document US 5,816,706 also performs two measurements with different thermal conductivities with known ratios. However, the conductivity is not locally variable, but rather is set to a different fixed value at different locations of the device. This has the risk of variability within the object being measured, such as the difference in blood perfusion in the body and the difference in contact resistance between the object and the two stacks of sensors, which can lead to inaccuracies in the measurement. Introduce. Furthermore, the need for different positions at mutual distances makes the device somewhat larger. Moreover, manufacturing devices with different thermal conductivities with known time independent ratios causes manufacturing problems. All these problems are not present in the present invention.

  The modulation means can be means for which the thermal coupling is variable, hence passive means, or means for changing the thermal coupling, hence active means. Passive means may be user configurable, for example, by moving or the like, whereas active modulation means may be set by the device itself or by a control signal or the like. This choice between active and passive modulation means is intended to be provided throughout this disclosure.

  In a specific embodiment of the invention, the structure comprises a first structure part on its first side and a second structure part on its second side, the modulation means comprising said first and second It is configured to change the thermal coupling of the structural part.

  In this embodiment, the structure that may be a separate part in the device or that may substantially contain the whole other than two sensors is divided into two sub-parts, i.e. structural parts, in each case one structure. The portion corresponds to one of the first side and the second stroke. By introducing a variable thermal coupling between the first structural part and the second structural part, the desired variable temperature at the second temperature sensor can be achieved. This is because different thermal bonds introduce different heat fluxes. This then causes a temperature change, which can be measured, for example, by sampling, which then allows the core temperature to be calculated, and so forth. According to the invention, in an alternative or additional embodiment, the modulation means are arranged to change the thermal coupling between the second side at the location of the second temperature sensor and the surroundings. This is another way of providing a variable total heat flow. Examples are elucidated below.

  Specifically, the modulating means is configured to provide a variable distance between the first and second structural parts. The variable distance ensures a well-controllable variable thermal coupling, which decreases with increasing distance.

  In a special embodiment, at least one of the first and second structural parts comprises a projecting pin, the projecting pin having its tip facing the opposite of the at least one of the first and second structural parts. Oriented to face. A small change in the distance between the protruding tip, i.e. its apex, and the opposite structural part leads to a large change in the overall heat conduction. Such high sensitivity to small distance variations is due to the temperature field “crowding” near the tip of the pin. It enables robust implementation at low cost.

  Here, it is advantageous for the modulation means to change the distance between the tip of the pin and vice versa, or in particular if the actuator is controlled by a control unit.

  In a specific embodiment, at least one of the first and second structural parts comprises a first material (air, vacuum, fluid or solid material) with a first specific thermal conductivity, and the protruding pin is A second material with a second specific thermal conductivity higher than the first specific thermal conductivity, preferably comprising at least one of a metal, more preferably aluminum, copper and silver . By providing a pin with high thermal conductivity, the temperature field crowding is more pronounced, which results in higher sensitivity. The pins can be made from any highly thermally conductive material and graphite is suitable, but is preferably made from metal.

  In a specific embodiment, the protruding pin is movable with respect to the at least one opposite one of the first and second parts, preferably a modulation means is arranged for moving the protruding pin. Is done. Here, the modulation means can be considered as a movable protruding pin itself. If the modulation means are arranged to move the protruding pins, they are considered to be pin moving means, or even a combination of pins and pin moving means. In all cases in this embodiment, it is sufficient if the pin itself is movable. The structural parts need not be movable relative to each other, and the pins may be movable through openings in one or both of the structural parts. It is also possible for the pin to be rotatable or tiltable, for example, in order to provide different thermal coupling between the two structural parts.

  In a special embodiment, the modulation means comprise a piezoelectric actuator for moving the protruding pin. Piezoelectric actuators are well suited for moving a pin over a small distance. However, any other suitable actuator for moving the protruding pin, such as a coil actuator, can be used.

  In an advantageous embodiment, the structure comprises a cavity and the modulation means comprise moving means for moving the thermal coupling material at least partially into the cavity. In this embodiment, in the first situation, the cavity is, for example, substantially empty between the first and second temperature sensors. In the second situation, the moving means moves the thermal coupling material into a cavity between the first and second temperature sensors. The presence of the thermal bonding material can result in different thermal bonding as desired in the present invention. It is possible for the moving means to move the thermal bonding material into the cavity, thereby moving the amount of other binder already present in the cavity.

  Specifically, the moving means is a fan or a pump, and the material includes air or gas. By allowing air or other gases to move or pump into the cavity or along a portion of the device, the coupling can be altered, especially if the ambient temperature is different from the surface temperature of the object. A fan or pump consumes a certain amount of energy, which is largely much less than the energy required to heat the material.

  In other embodiments, the thermal bonding material has a thermal conductivity that is at least twice the thermal conductivity of the atmosphere at room temperature. Preferably, the thermal conductivity is at least 1 W / mK, more preferably at least 50 W / mK. In this way, there is a significant difference in thermal coupling between the first and second structures with and without the thermal coupling material. In general, the greater the difference, the more accurate the measurement.

  In other embodiments, the second side thermal coupling to the environment is variable, and preferably modulation means are arranged to (actively) change the thermal coupling. Again, means are provided for changing the heat flux without substantially using energy by simply affecting the way heat flux is emitted to or taken from it.

  In a special embodiment, the structure includes a variable heat sink. Specifically, the variable heat sink is thermally coupled to the second structural part or, for example, between the first and second structural parts. Since it is variable, it can reduce (sink) various heat fluxes. The heat sink may include a fixed heat sink element and a heat flux modulating element having a variable thermal resistance. The heat flux modulating element can be provided on the one hand between any of the first side, the second side, and the heat sink and any of the second side, the heat sink, and the surroundings (not the same). Here, as throughout the text, the term “element” may refer to both a single entity and an assembly of two or more structural parts. Furthermore, as in all cases, it is preferred if the change in heat flux is at least 10% for measurements that give sufficiently accurate results.

  Specifically, the heat sink is variably thermally coupled to the structure, specifically to the second side, using a movable thermal conductor that can be contacted with the heat sink or vice versa. obtain.

  In some embodiments, the heat sink includes at least a first heat sink portion that is movable relative to at least one of the second heat sink portion and the first structural portion. Preferably, the first heat sink part is rotatable and / or translatable so that the variable part of the second part is shielded from the surroundings or both. This is a simple embodiment of a variable heat sink, which allows variable contact with the surroundings and thus can sink a variable heat flux to the surroundings. This in turn allows different temperatures and temporal derivatives of temperature to be reached at the second temperature sensor.

  In a specific embodiment, the modulation means for reducing the temperature includes an active cooler for cooling the second sensor. Again, this is not intended to cool only the second sensor, it is intended to cool the second sensor, its vicinity, or the second side portion in its vicinity. This is the second sensor and reflects the new temperature built in or near it. The active cooler means is preferably at least a second sensor, at or near the second sensor, when the active cooler means is switched on and thereby becomes energy consuming. Arranged to draw external heat energy from the part. Although the temperature at the second temperature sensor can be lowered by changing the heat flux, providing an active cooler means allows more control over cooling and often that lower temperatures are achieved. enable.

  Advantageously, the cooler means has a variable cooling power, which can be set to at least two different non-zero values. This is the case when the device consumes energy in both situations. However, the advantage is that the apparatus is still safe for the user as a whole, whereas the temperature difference and thus the measurement accuracy can be higher.

  In a specific embodiment, the cooler means includes a Peltier element. Peltier elements are cooler means that are small, efficient and well controllable. Furthermore, the Peltier element also allows heating, which provides the possibility of performing a first measurement with active cooler means and a second measurement with active heater means. This allows a very large difference in the second temperature sensor and thus a very high accuracy.

  In other embodiments, the cooler means includes a vaporizer for vaporizing the fluid. Such a vaporizer forms a suitable means for reducing the temperature with the second temperature sensor without consuming energy. In a special embodiment, the vaporizer includes pump means for moving the fluid. Preferably, the vaporizer comprises a fluid reservoir, in particular a fluid reservoir filled with fluid. This fluid is preferably a fluid that vaporizes rapidly and / or with a large latent heat. An example can be ethanol.

  In a specific embodiment, the apparatus includes fan means arranged to move gas, preferably air, along at least a portion of the second side of the structure. The fan means provides a suitable and good control means for lowering the temperature with the second temperature sensor. This is especially true when the fan means cooperates with a heat sink, and also applies when the device includes a vaporizer, preferably both. The combination of vaporizer and fan means, in some cases, with a heat sink, provides a very effective means of lowering the temperature, which is also well controllable because it is independent of ambient temperature or air flow. Preferably, the fan means is fan means that can be variably controlled to select an appropriate temperature.

  In certain embodiments, the apparatus includes a read device for reading temperature signals from the first and second temperature sensors. Such a readout device can be a display for displaying the respective temperatures. It can be a device that outputs an electrical or digital signal corresponding to temperature or any other suitable output device.

In a special embodiment, the apparatus includes a calculation unit arranged to calculate the core temperature from the respective temperature signals from the first and second temperature sensors. The calculation unit may include a computer device or a device for calculating any other circuit configuration or temperature, for example. The calculation unit can be programmed to calculate the temperature according to mathematical techniques known in the prior art. One method that can be used is the following equation:

の指数関数的曲線によって近似され得るし、
（外２）

での定常状態温度は、指数
（外３）

により温度曲線の利用可能な初期部分を適合することによって推定され得る。指数の係数Ａ、Ｂ、及び、Ｃを決定した後、定常状態温度
（外４）

は、
（外５）

であるので、推定され得る。次に、それぞれの定常状態温度で、適切な数式が、中核身体温度を見出すために使用され得る。例えば、人は以下のような数式を使用し得る。

ここで、
Ｔ_１ａ及びＴ_１ｂは、第一熱束状況における第一側及び第二側の温度であり、
Ｔ_２ａ及びＴ_２ｂは、第二熱束状況における第一側及び第二側の温度であり、

であり、ここで、
Ｋ_１及びＫ_２は、第一状態及び第二状態のそれぞれにおける熱伝導率である。この場合には、第一側と第二側との間の熱伝導率は優勢係数であり、いずれも既知であり、或いは、当業者に既知の技法に従って、さらなる測定から決定されると推定される。 This mathematical formula and its quantity will be clarified in the description of the drawings. A general note to be made regarding this formula is that a larger temperature difference generally results in a larger time derivative of T _s , which allows a more precise determination of the core temperature. For this equation, temperature trends are measured and a large number of measurements are required. Alternative measuring methods can be used and the device, in particular the control unit and the calculation unit, can be implemented correspondingly. An example is to continuously measure the temperature of two sensors in two steady states corresponding to two different and constant heat fluxes by switching with a modulation means. Equally possible is a mixture of such methods, for example a method in which the steady state temperature is extrapolated by a temperature reading from the sensor. Such extrapolation is almost always a form.
(Outside 1)

Can be approximated by an exponential curve of
(Outside 2)

The steady-state temperature at is the exponent (outside 3)

Can be estimated by fitting the available initial part of the temperature curve. After determining the exponential coefficients A, B and C, the steady state temperature (outside 4)

Is
(Outside 5)

Therefore, it can be estimated. Then, at each steady state temperature, an appropriate formula can be used to find the core body temperature. For example, a person may use the following formula:

here,
T _1a and T _1b are the temperature of the first side and the second side of the first heat flux conditions,
T _2a and T _2b are the temperatures on the first side and the second side in the second heat flux situation,

And where
K ₁ and K ₂ are thermal conductivities in the first state and the second state, respectively. In this case, the thermal conductivity between the first side and the second side is the dominance coefficient, both are known or estimated to be determined from further measurements according to techniques known to those skilled in the art. The

  In any case, the person skilled in the art has a number of ways to derive the core temperature from the measured temperatures on the first and second sides.

In an advantageous embodiment, the device comprises a control unit, which is arranged to control the modulation means. In this way, the control unit can adapt the modulation means if a particular change in the setting of the modulation means is advantageous for determining the core temperature. For example, depending on the T _s, different settings, etc. for the different variations or cooler unit of thermal coupling can be advantageous. Preferably, the control unit is configured to maintain each heat flux at a substantially constant level to improve accuracy. Advantageously, the control unit comprises a calculation unit, or in other words, the control unit and the calculation unit are preferably integrated into one unit.

  In a specific embodiment, the modulation means can be set in a plurality of states, preferably two states with different predetermined heat fluxes between the first side and the second side. In this embodiment, using the example already given above, the modulation means may set two heat fluxes to obtain two different situations, each with a different equilibrium temperature or temperature evolution curve. More preferably, the control unit is configured to switch between a plurality of, specifically two, states with different frequencies so that the resulting heat flux can be controlled to a predetermined substantially constant level. Is done. In this way, in principle, any heat flux between two extreme values, ie low conductivity and high conductivity, can be set, so the device needs to depend on such extreme values. Without, it may be configured to provide a sufficiently different heat flux. While it is possible to provide a continuously variable heat flux with suitable modulation means, having a discontinuous value may have advantages with respect to the stability and accuracy of the device. The method of control can be compared to a pulse width modulation method or high frequency time division multiplexing between steady states. By adjusting the ratio of the time intervals while the device is in different states, different effective thermal couplings can be achieved. Preferably, the switching frequency should be substantially higher than the rate of heat propagation through the structure, typically in the range of 1-10 Hz. A relay type switch or any other mechanical structure may be used for that purpose.

  In a special embodiment, the apparatus obtains a first respective temperature signal from the first and second temperature sensors in a situation where the heat flux has a first value, and the situation where the heat flux has a second value. A control unit configured to obtain a second respective temperature signal from the first and second temperature sensors and to calculate a core temperature from the first and second temperature signals.

  This is an embodiment in which the device itself can perform the required measurements to determine the core temperature. It is also possible to provide a device comprising a transmitter for transmitting the temperature value to an external computing unit. This latter embodiment may be useful for centrally monitoring the core temperature of various subjects, such as various patients in a hospital.

  In a further advantageous embodiment, the device according to the invention comprises a light sensor, preferably a SpO2 and / or StO2 sensor, comprising a light source, preferably comprising at least one LED. The modulation means according to the invention allows the advantage of a safer cryogenic measurement, but it is not excluded to include a heater element to obtain a modified heat flux. Advantageously, in the case of SpO2 and / or StO2 sensors, the light source is present and / or a thermistor. In either case, they tend to generate heat when functioning. This heat can be used to generate a variable heat flow. In other words, in any case, a very efficient use of the generated heat is performed. Preferably, the antigen comprises at least one LED. Such a light source is extremely compact and can be provided, for example, in proximity to the second temperature sensor.

  In an advantageous embodiment, the first side has an outwardly curved shape, and preferably the structure is preferably outward so that the portion where the first temperature sensor is present projects from the first side. A member having a curved shape is included. In this way, the first temperature sensor can contact the object to be measured in an appropriate manner and provide reliable contact. In particular, a member for that function can be provided on which the first temperature sensor is mounted or attachable. Preferably, the member is arranged to apply a spring force or elasticity that can push the first side and thus push the first temperature sensor onto the object.

  Thereby, advantageously, the member comprises a flexible material, preferably a spring, in particular a leaf spring. Here, “flexibility” means that the shape can be visually changed when a normal force of a human finger is applied. The advantage of the member being flexible is that changes such as movement in the object to be measured, in particular the human body (skin), can be adapted more easily.

  Preferably, the member has a substantially uniform thickness. In such a case, the heat flow is flatter within the structure, specifically within the member. This greatly simplifies the computation and allows relatively simple approximations to be effective.

  In certain embodiments, the member is layered. Preferably, the member comprises a layer of Kapton ™ or Neopurine and / or a layer of good thermal conductor on at least one plane of the member. Such a layered structure allows for an equivalent heat distribution on the first and second sides of the member, advantageously on the first and second sides of the device as a whole. Again, this simplifies heat flow and calculations and increases the accuracy of temperature measurements. Here, if the thermal conductor has a thermal conductivity of at least 1 W / mK and preferably comprises a metal layer, the thermal conductor is good. In addition, other layers, preferably the central layer, include good insulation, such as Kapton ™ or Neopurine, which combines the desired elastic properties with low thermal conductivity. Other materials are not excluded.

  In an advantageous embodiment, the device includes a holding structure for holding the device in a stable position on the object. The device may be useful without such a retaining structure, for example by manually holding it in a desired position, but its usefulness may be increased by providing such a retaining structure. In that case, the device can be left unattached and still perform its function reliably. Specifically, the holding structure includes a member for fixing the device to the object and / or a side wall around the fixing means, and more preferably includes an adhesive layer and / or a strap. Such a side wall is advantageous in providing a preload on the member, which is useful for establishing positive contact with the object. Further, the securing means preferably includes an adhesive layer and / or a strap to secure the device to the object. Of course, depending on the object, other fixing means can also be envisaged.

  In a second aspect, the invention also relates to a method for measuring a core temperature of an object, the method comprising positioning a first temperature sensor in a position for measuring a surface temperature of the object, a second temperature A structure having a sensor and a first side and a second side, the first temperature sensor being on the first side and the second temperature sensor being on the second side, the structure being Positioning to be between the sensor, measuring the first temperature with the first temperature sensor and measuring the first temperature with the second temperature sensor, the heat flux between the first side and the second side Changing, measuring at least one second temperature with the first temperature sensor and measuring at least one second temperature with the second temperature sensor, and each first temperature and each at least one second temperature. Includes calculating the core temperature from the temperature. The method according to the invention is generally the counterpart of the device and provides approximately the same advantages, so they are generally not repeated here.

  A general note to be made here is that instead of the first and second temperatures, the first and second temperature trends are also useful. In other words, in each of the two situations, i.e. in different thermal coupling or active cooling or the like, the first and second temperatures or at least the first temperature are sampled in time. All this is further elucidated in the detailed description of the embodiments.

  In some embodiments, the heat flux is changed by changing the thermal coupling between the first side, the second side, and the surrounding first, and the first side, the second side, and the surrounding others. Is done. In these methods of controlling heat flux, such as changing the thermal conductivity between the first and second sides, or changing the thermal coupling between the second side and the surroundings, etc. Each possibility can be used.

  In a specific embodiment, the heat flux is changed by cooling the second side. This is the counterpart of the device according to the invention and includes an active cooler.

  Advantageously, in the method according to the invention, an apparatus according to the invention is used. In such cases, reliable core temperature measurements are possible in most cases with very low energy consumption and without the risk of combustion.

  The invention will now be described in more detail with reference to the drawings, which show a number of illustrative and non-limiting embodiments.

FIG. 2 is a schematic diagram showing an embodiment of an apparatus according to the invention. FIG. 2 is a schematic diagram showing an embodiment of an apparatus according to the invention. FIG. 2 is a schematic diagram showing an embodiment of an apparatus according to the invention. FIG. 2 is a schematic diagram showing an embodiment of an apparatus according to the invention. FIG. 2 is a schematic diagram that may be useful in understanding the present invention.

  The device is shown schematically in elevational section, not in full size.

  Figures 1a to 1e show various embodiments of the device according to the invention.

  The apparatus shown generally at 1 in FIG. 1a includes a first structural part 2 and a second structural part 3 comprising a first temperature sensor 4 and a second temperature sensor 5, respectively, the first temperature sensor and the second temperature sensor. Are connected to a control and / or calculation unit 6 (hereinafter control unit).

  Reference numeral 7 denotes an actuator, 8 denotes a heat conducting pin, and the device is positioned on the skin 9 of the body part.

  The device comprises a kind of double layer structure with temperature sensors 4 and 5 on each side. The distance between the two structural parts 2 and 3 can be changed using the actuator 7.

  The actuator can be an inflatable actuator, a piezoelectric actuator, or the like. They can be coupled or connected to the control unit 6. By changing the distance in the direction of arrow A, the thermal coupling between the first structural part 2 and the second structural part 3 can be changed. The sensitivity of changes in this coupling can be increased with a selective pin 8. The tip or top end of this pin 8 can be positioned on or close to the opposite structural part in the proximity of the first structural part 2 and the second structural part 3. By operating the actuator 7, the distance can be increased and the thermal coupling can be strongly reduced.

  For example, the pin 8 is made of a highly conductive material such as aluminum or copper, while the first structural portion 2 and the second structural portion 3 can also be made of a conductive material such as a metal. The actuator 7 can also be conductive but can also be adiabatic to prevent affecting the measurement.

  The first temperature sensor and the second temperature sensor can be any useful type of temperature sensor, such as a thermistor, thermocouple, NTC / PTC resistor, and the like. The sensors 4, 5 can be attached to the structural parts 2, 3 or can be connected to them via wires (not shown). The sensors are connected to the control unit 6, which preferably includes a display for indicating the respective temperature. Preferably, the control unit 6 includes a calculation unit for measuring the core temperature and is arranged to display the temperature.

  The device 1 is shown positioned on the skin 9 of the body part. It can be positioned on any kind of container with a specific temperature content to be measured, such as baby milk or the like.

  FIG. 1 b shows an embodiment comprising a van 10, a heat sink 11, a fluid container 12 containing a fluid 13, and a passage 14 in the second structural part 3. As a general note, like parts are denoted by the same reference numerals in all figures.

  The fan is arranged to move air through the section between the first structural part 2 and the second structural part 3. This changes the thermal coupling between those structural parts. If a heat sink 11 is provided, this change is increased and it is preferably made of a thermally good conductive material such as aluminum or copper. Multiple heat sinks can be provided and they can also be provided on the first structural part 2 or both.

  Alternatively or additionally, a fluid container 12 is provided comprising a fluid that is easily vaporized. This fluid 13 can reach the space between the structural parts 2, 3 through the passage 14. There, the fluid evaporates and becomes a vaporized fluid cloud 15. Latent heat cools the device and changes the heat flux. The fan 10 increases this effect through forced air movement, for example in the direction of the arrow.

  FIG. 1 c shows an embodiment of the device comprising a core material 16 sandwiched between a first conductive layer 17 and a second conductive layer 18.

  Reference numeral 19 denotes a Peltier element, and reference numerals 20-1 and 20-2 denote first and second movable heat sink portions.

  This embodiment shows a sandwich structure in which the core material 16, in this case, for example, Kapton ™, is sandwiched between two conductive layers 17 and 18, such as an aluminum layer. ing. The latter element ensures a homogeneous temperature distribution on both sides of the device.

  The Peltier element 19 or other cooling device is provided in thermal contact with the second side, ie the second conductive layer 2. When the Peltier element is switched on, the temperature on the second side is lowered, which can cause a temperature change for the second temperature sensor 5. Reference numerals 20-1 and 20-2 denote first and second movable heat sink portions. The first heat sink portion 20-1 is shown moved open along the direction of arrow B, and is similar for the second portion 20-2. By opening or closing the movable heat sink portions 20-1, 20-2, the thermal coupling of the second side, second conductive layer 18 can be altered. It again ensures a different heat flux and thus a different temperature at the second temperature sensor 5.

  FIG. 1d shows a device more suitable for use in the ear or similar area. The apparatus includes a substrate 21, at least one LED 22, and at least one light sensor 23.

  The substrate 21 can be shaped, for example, so that it can be immediately inserted into the ear canal. Substrate 21 may include a somewhat flexible shape restoring material such as a variety of rubbers. The device according to FIG. 1d is embodied as a combination of core temperature sensors with SpO2 or StO2 sensors. Such sensors include at least one, preferably at least two LEDs 22 and a light sensor 23, as is well known.

  When using this device, the heat flux through the device from the first temperature sensor 4 to the second temperature sensor 5 through the substrate 21 can be changed by operating one or more LEDs 22. These generate heat, which is carried through the substrate 21, thus changing the temperature. This embodiment is a device suitable not only for inaccurate inner ear skin surface temperature or tympanic temperature, but also for example both blood and / or tissue oxygenation and body core temperature. It is noted that details regarding measuring blood and / or device oxygenation are considered known to those skilled in the art and will not be discussed further here.

  FIG. 1e schematically shows an embodiment of the device comprising a suitable fixing assembly. The apparatus includes a flexible member 24 within a holding structure 25 that includes a securing means 26. Also illustrated are preferred positions 4 and 5 for the first and second temperature sensors, and respective alternative positions 4 'and 5'.

  This embodiment includes a flexible member 24 made of, for example, neoprene. The flexible member 24 protrudes outward. Preferably, the first sensor 4 is present on the top of the bulge of the flexible member 24. The member 24 is fixed between fixing means 26 on the holding structure 24, which can be integral.

  This device ensures a good coupling between the first sensor 4 and the object to be measured, such as a body part. In use, a person moves a body part, which can cause movement of the device relative to the body part. This embodiment reduces the risk of inadvertent movement of the device relative to the body part.

  The retaining means 25 includes means for attaching the device to the body part as a whole, such as an adhesive strip strap (not shown). The securing means may simply be a clamp for securing the flexible member, or any other device or means with a similar purpose.

  If desired, a general note should be made here that the various embodiments, or even parts thereof, can be combined. For example, the layered structure of the embodiment of FIG. 1c can be combined with the flexible member 24 of the device of FIG. 1e. A person skilled in the art can easily make and derive such a combination by means of the drawings and the general introductory part of this application, but this is not necessarily the case.

  FIG. 2 is a schematic diagram that may be useful in understanding the present invention.

In the drawing, the device 1 is positioned on a body part 28. The apparatus schematically includes first and second structural parts 2, 3 comprising first and second temperature sensors 4, 5 and a medium 27 therebetween. Medium has a thickness of h _d, the heat conductivity lambda _d.

  The body part 28 generally and schematically includes a skin 9 and a body core 29, 30 representing the skin surface and 31 representing a virtual interface between the skin and the body core.

The skin, ie, the layer to be taken in the model, as will be explained below, has a thickness h _s and a thermal conductivity λ _s .

  In the model, for example, the temperature profile in the skin is essentially linear in depth, ranging from the true body core temperature in the body core 29 to the skin surface temperature or the temperature at the first sensor 4.

ここで、
Ｔ＝温度
ｔ＝時間
ｘ＝深さ
α＝λ／_ρｃ_ｐ
λ＝熱伝導率
ρ＝密度
ｃ_ｐ＝比熱
ｑ_ｓ＝皮膚表面３０を通じる熱束 The body core temperature Tcore can be determined by solving the system equation according to:

here,
T = temperature t = time x = depth α = λ / _ρ c _p
λ = thermal conductivity ρ = density c _p = specific heat q _s = heat flux through the skin surface 30

The amount q _s can be measured using two temperature sensors 4 and 5. After rewriting the above equation with an estimate that the thermal response time of the medium 27 is faster than that of the skin, ie α _d >> α _s , this results in:

と近似され得ると想定すると、そこから

ということになる。 Furthermore, the linear temperature profile at depth, qc,

Assuming that

It turns out that.

及び
（外７）

であるのに対し、
量Ｔ_ｓ，ｑ_ｓ、及び、
（外８）

は、測定される量である。これらの量を一連の異なる時間の瞬間ｔ_ｉで測定することによって、以下の結合方程式の行列（マトリックス）が得られ、

ここで、

である。 The unknown quantity is
(Outside 6)

And (outside 7)

Whereas
The quantities T _s , q _s , and
(Outside 8)

Is the amount to be measured. By measuring these quantities at a series of different time instants t _i , the following matrix of coupling equations is obtained:

here,

It is.

及び
（外１０）

が、測定中に時間非依存的であるということである。方程式のシステムは、例えば、少なくとも二乗最小化（ＬＭＳ）法を用いて、或いは、如何なる他の適切な数学的方法をも用いて解かれ得る。その場合には、これは身体核心温度をもたらし、皮膚表面を通じる熱束ももたらす。よって、一般的には、本発明に従った装置及び方法は、中核身体温度だけでなく他の量を決定するためにも使用され得ることに留意のこと。 One estimate is
(Outside 9)

And (outside 10)

Is time-independent during the measurement. The system of equations can be solved, for example, using at least the square minimization (LMS) method, or using any other suitable mathematical method. In that case, this results in body core temperature and also heat flux through the skin surface. Thus, it should be noted that, in general, the apparatus and method according to the present invention can be used to determine other quantities as well as the core body temperature.

よりも遅く変化する期間中のサンプリング瞬間に達する。 Sampling instant (sampling Moment) t _i should be selected by the estimation for the linearity of the dT / dt in the temperature profile and depth holding it skin temperature T _s characteristic propagation time in the skin (outer 11)

A sampling instant during a slower changing period is reached.

  The embodiments and methods currently presented herein are considered to be illustrative and non-limiting only, and the scope should be determined by the appended claims.

Claims (14)

A device for measuring the core temperature of an object,
A structure having a first side to be positioned with respect to the object and a second side substantially opposite the position side;
A first temperature sensor positioned and arranged to measure temperature on the first side;
A second temperature sensor positioned and arranged to measure temperature on the second side;
Including modulation means for lowering the temperature of the second temperature sensor by changing the heat flux between the first side and the second side at the position of the second temperature sensor;
apparatus.   The modulation means is configured to switch between a first heat flux state and a second heat flux state, and the energy consumption of the device in its steady state is essentially unchanged, specifically, The apparatus of claim 1, wherein steady state energy consumption is substantially zero for both the first heat flux state and the second heat flux state.   The thermal coupling between the first side, the second side, and the surrounding first, and the first side, the second side, and the other surrounding is variable, and the modulation means includes: In particular, the apparatus of any one of claims 1-2, wherein the apparatus is configured to change the thermal coupling, and more specifically, the thermal conductivity of the structure.   The structure includes a first structure portion on a first side thereof and a second structure portion on a second side thereof, wherein the modulation means provides thermal coupling between the first structure portion and the second structure portion. 4. An apparatus according to any one of claims 1 to 3, wherein the apparatus is configured to change.   The apparatus of claim 4, wherein the modulating means is configured to provide a variable distance between the first structural portion and the second structural portion.   6. Apparatus according to any one of the preceding claims, wherein the structure comprises a cavity and the modulating means comprises moving means for moving a thermal coupling material at least partially into the cavity. .   The structure includes a variable heat sink, and specifically includes at least a second heat sink portion and a first heat sink portion movable relative to at least one of the first structure portions, the first heat sink portion being 7. Any one of claims 3 to 6, preferably rotatable, or translatable so that the variable area of the second part is shielded from the surroundings, or both. The device according to item.   The modulation means for lowering the temperature comprises active cooling means for cooling the second sensor, such as a Peltier element, and / or a vaporizer for vaporizing a fluid, and / or the first of the structure. 8. A device according to any one of the preceding claims, comprising a fan arranged to move gas, preferably air, along at least part of the two sides.   9. Apparatus according to any one of the preceding claims, comprising a calculation unit configured to calculate a core temperature from respective temperature signals from the first temperature sensor and the second temperature sensor.   Each temperature signal is acquired from the first temperature sensor and the second temperature sensor in a situation where the sacrificial heat flux has a first value, and the first temperature sensor in a state where the heat flux has a second value. And a control unit arranged to obtain a respective temperature signal from the second temperature sensor and to calculate the core temperature from the respective first and second temperature signals. The apparatus of any one of them.   11. Apparatus according to any one of the preceding claims, further comprising a light sensor comprising a light source, preferably comprising at least one LED, preferably a SpO2 and / or StO2 sensor.   The first side has an outwardly curved shape, and preferably the structure includes a member having an outwardly curved shape, specifically, the member is a flexible material, preferably The device according to any one of the preceding claims, comprising a spring, more preferably a leaf spring. A method for measuring the core temperature of an object,
Positioning a first temperature sensor at a position for measuring the surface temperature of the object;
A second temperature sensor and a structure having a first side and a second side, wherein the first temperature sensor is on the first side, the second temperature sensor is on the second side, and the structure is Positioning the structure to exist between the first temperature sensor and the second sensor with thermal coupling between the first side and the second side;
Measuring the first temperature with the first temperature sensor and measuring the first temperature with the second temperature sensor;
Changing the heat flux between the first side and the second side;
Measuring at least one second temperature with the first temperature sensor, and measuring at least one second temperature with the second temperature sensor; and
Calculating the core temperature from the respective first temperature and the respective at least one second temperature;
Method.   The heat flux changes the thermal coupling between the first side, the second side, and the surrounding first, and the first side, the second side, and the surrounding others. 14. The method according to claim 13, wherein the method is modified by cooling and / or cooling the second side, in particular the apparatus according to any one of claims 1-13.

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