TW528862B - Infrared gun-type ear-temperature thermometer - Google Patents

Abstract

The present invention provides an infrared gun-type ear-temperature thermometer, which has an optical system, an infrared detector, an environmental temperature sensor, a display unit and a signal processing unit. The infrared detector converts infrared signal into electrical signal and detects a reference temperature. The environmental temperature sensor is arranged in the vicinity of the optical system to sense the rapidly changed environmental temperature. The signal processing unit receives signals from the infrared detector and the environmental temperature sensor and generates a compensation value by an algorithm. The compensation value is used to adjust the read temperature value and maintain a high accuracy of the gun-type ear-temperature thermometer when the temperature is rapidly changed, so that the gun-type ear-temperature thermometer can be used in a non-constant temperature condition.

Description

528862 V. Description of the invention (1) Background of the invention The present invention relates to an infrared ear thermometer, which is inserted into the ear to read the body temperature. All the traditional infrared ear thermometers are sensitive to the ambient temperature due to the detector's insensitivity and receive radiation from the waveguide of the optical system except the ear canal and eardrum, making it sensitive and accurate. It is poor when the ambient temperature changes; in most infrared ear thermometers, there is a temperature reference sensor to compensate the insensitivity of the temperature change; however, if the ambient temperature changes rapidly, the compensation may not be effective and Correctly follow the temperature change of the detector According to the infrared medical thermometer disclosed in US Pat. No. 4,895,1 64 patent, the combination of the waveguide and the bat-shot detector must be operated in a uniform temperature state; this thermometer is especially It has a heat-conducting unit, which is built to keep the temperature in a uniform temperature state; however, when the ambient temperature changes sharply, maintaining this uniform temperature state is not easy to maintain. For example, if the thermometer is placed in a warm room (such as 30 ° C) Move to a cold room (such as 15 ° C), then the average temperature state will be destroyed, and it must take half an hour, one hour or more to reach the new average temperature. Balanced state. Another radiation medical thermometer disclosed in US Pat. 5,024,533 has a waveguide probe and an infrared detector, a detection signal processing unit, a body temperature operation unit and a display unit; the body temperature operation unit receives Infrared data from the infrared detector and temperature sensing data from the two temperature reference sensors TIBi ^ page 5 528862, these temperature reference materials must be considered in the temperature equalization of the waveguide and the infrared detector to accurately calculate Body temperature; these two temperature reference sensors are set on the infrared detector and the waveguide to detect the temperature difference between the infrared detector and the waveguide. In this case, the body temperature is at a non-constant temperature. In the state, it is caused by the difference between the two temperature reference sensors, but this situation is not so simple. First of all, the waveguide is not the only source that generates measurement errors in communication with the infrared detector. All optical systems The inner wall of the package containing the infrared detector, the detector window and the probe itself have radiation to the detector unit, and these radiation must be all In order to meet the requirements of accuracy under non-uniform temperature conditions; at the same time, the ambient temperature changes may be diversified, the ambient temperature may be uncertain in the direction and time of the change, if the thermometer is placed in a chaotic and rapid temperature When the space is changed, the temperature difference between the detector and the waveguide may be zero at a certain moment, but the optical system of the thermometer is not actually in a uniform temperature state, so its compensation may not be correct. SUMMARY OF THE INVENTION The main object of the present invention is to provide an infrared ear thermometer for accurately reading body temperature from an external ear canal without having to wait for a constant temperature state during rapid ambient temperature changes. Another object of the present invention is to provide a simpler and more efficient method for generating a compensation chirp, which is used to eliminate reading errors caused by the ambient temperature, the temperature difference between the infrared detector and the optical system; Maintain the accuracy of the infrared ear thermometer. In order to achieve the above object, the infrared ear thermometer of the present invention has an optical system βϊ 528862. 5. Description of the invention (3) system, an infrared detector, an ambient temperature sensor, a display unit and a signal processing unit; Wherein, the infrared detector further includes an infrared sensor and a temperature reference sensor; the infrared sensor is placed on the substrate and the temperature reference sensor is disposed near the substrate of the infrared detector to separately The infrared signal is converted into an electrical signal and senses the reference temperature. The ambient temperature sensor is installed near the optical system to detect the rapidly changing ambient temperature. The signal processing unit receives the signal from the temperature sensor and generates a mathematical algorithm. The compensation 値 is used to correct the temperature reading 校正 and maintain the high accuracy of the ear temperature gun under rapid temperature changes. The detailed description of the preferred embodiment is based on FIG. 1. A cross-sectional view of the present invention, which has a casing 1, an infrared detector 1 1, a waveguide 1, 2. an ambient temperature sensor 1, 3. a signal processing. A unit 14 and a display unit 15; as shown in FIG. 3, one end of the waveguide 12 and the infrared rays directly collected from a measured object 31 are radiated from the other end of the waveguide 12 and the infrared detector 11 Connected, the infrared detector Π (shown in Figure 3) converts the infrared radiation into electrical signals and transmits them to the signal processing unit 1 4; the ambient temperature sensor 13 is set close to the optical system (waveguide 12 and Infrared detector Π) to detect changes in the ambient temperature. The ambient temperature sensor 13 converts the ambient temperature changes into electrical signals and transmits them to the signal processing unit 14 (as shown in Figure 3); the display unit 15 is set at On the chassis, it displays the temperature of the signal processing unit 14 after processing the signals from the infrared detector 11 and the ambient temperature sensor 13 (as shown in Figure 3). At the same time, the infrared detector 11 includes an infrared sensor. Sensor Π 1 and a temperature reference sensor 11 2 Assume

(I 528862 V. Description of the invention (4) It is placed on the substrate 114 of the infrared detector 11 and near the substrate Π4 to receive infrared radiation and sense temperature changes. Among them, the temperature reference sensor 112 is used to detect The temperature of the substrate 114 of the infrared detector Π. The following is a description of the experimental derivation method of the calculation formula of the temperature compensation method. Please refer to FIG. 4. The embodiment of the experiment has three temperature reference sensors set at different positions, respectively. Abbreviated as THRwg 41, THRean 42, THR & 43, of which THRwg 41 is located in the front section of the waveguide 12, THRcan 42 is located on the metal packaging wall of the infrared detector 11, and THRair 43 is located near the optical system (waveguide 12 and infrared detector 11). The right infrared ear thermometer withstands a temperature change from Ta to Ta + T 0, and is near THRau 43 near the optical system (waveguide 12 and infrared detector Π). It is assumed to have a heat capacity Cair and a heat conductance GaK from the environment, which heat capacity is defined as ·

Cair-dQ / dT (1) where, when the temperature change is dT, dQ is the increased heat of storage; the thermal conductance Gau is defined to have the following relationship: >

Pl = Gair * ((TO + Ta) * u (t) -T (〇) (2) where P1 is the heat flow from the environment to the temperature g ten, and u (t) is a * step function; the THRair The temperature of 43 is dominated by the following equation: Page 8 528862 V. Description of the invention (5)

Cair * dT (t) / dt = Pl * u (t) (3)

Replace PI with formula (2)

Cair * dT (t) / dt + Gair * T (t) = G a i r * (T 0 + Ta) * u (t) (4) Use Laplace transformation to get the solution:

Cair * (s * T (s)-Ta) + Gair * T (s) = Gair * (TO + Ta) / s (5) By the formula (4) T (s) = Ta / (s + Gair / Ca ! r) + ((Ta + TO) * Gair / Cair) / (S * (S + G air / Cair)) (6) Let Gair air) to inverse Laplace transform (6) and plot the resulting solution T⑴ In Figure 5:

Ta, r (t) = TO * (l-exp (.t / (r air))) + Ta (7) where r air is the temperature time constant at THRair 43, which can be obtained by experimental tests. ΊΒ1 ^ 528862 V. Description of the invention (7) In the actual operating environment, the ambient temperature is random in direction and time; Formula (4) must be written as:

Cair * dT (t) / dt + Gair * T (t) = Gair * ((Ta + TO) * u (t). (Ta + TO) * u (t-tl) + (Ta + Tl) * u (t-tl)-(Ta + Tl) * u (t-t2) + (Ta + T2) * u (t-t2) -... (10)

Cair * dT (t) / dt + Gair * T (t) = G air * ((Ta + T 0) * u (t) + Σ (η = 1 ～ N) ((Tn-Tn-l) * u (t-tn))) (11) wherein Tn may be positive or negative. Based on Laplace's transformation and coincidence principle, the temperature Ta, Jt) can be obtained: Tair (t) = Ta + T0 * (1 -exp (-t / (r air))) + Σ (η = 1 ～ N) ((Tn-Tn-1) * (l-exp (-(t-tn) / (r air))) * u (t-tn)) (12) where Tair (t), rair and Ta are already Knowing the constant, if the time tn is also known, then TO ~ Tη can be calculated; the method of obtaining the random time tn is described as follows: First, consider the experimental test thermometer embodiment (shown in Figure 4) that only bears at t = 0 A rapid temperature change T0 is as shown in formula (7); before the time t = 0, the thermometer is maintained at a constant temperature state Ta. After the thermometer is connected to the power supply, 1HI ^ page 11 528862 V. Description of the invention (8) Thermometer signal processing unit continuous measurement and measurement temperature Tair (t) and its slope dTair (t) / dt, Tair (t) differentiates time dTair (t) / dt = (TO / τ air) * exp (-t / r air) (13) Because the temperature time constant rair is smaller than rean, rWg, and rsen (time constants of temperature reference sensor 112 (hereinafter referred to as THRsen 112)), the reaction speed of THRair 43 and the room temperature at t = t0 The ability to detect rapid temperature changes is faster and more powerful than THRcan 42, THRwg 41 or THRsen 112. That is, the time differential of Tair (t) is used to determine whether the ambient temperature of the thermometer has changed excessively. The reason is fast; when the slope of Tair (t) is larger than a preset value (such as 3 / r ai0, the thermometer must be positive). At a rapidly changing ambient temperature, the time is set to t = 〇 as shown in Figure 5. When the time moves from t = 0, the Tair (t) slope shown in Figure 7 gradually decreases, and finally changes It is 0 as in formula (1 3). When the time is larger than the preset 値 (such as 10 times the temperature time constant r air), the slope of Tair 接近 is close to 0. At the same time, because all temperatures TaU (t), Tsen, Tean (丨) and Twg⑴ are the same as shown in Fig. 6, and reach another constant temperature state, Ta + TO; if t = tl, the ambient temperature changes from Ta + TO to Ta + Tl, then in formula (12) Suppose N = 1 to find T ai I (t):

Tair (t) = Ta + T0 * (1-exp (-t / (r air))) + (but 1-but 0 ”(l-exp (_ (t-tl) / (r air))) * u (t-tl)) (14) Two conditions must be considered; the first condition is shown in Figure 8, when τι > το, when t = tl, the dTair (t) / dt 値 will become larger Instead of the above !! Page 12 528862 Fifth, the description of the invention (9) is reduced to 0, at this time the timer of 10 times r heart will be set to 0 to restart the time; because Tair (t), Ta, T0 and r air is known, and Ding 1 can be calculated mathematically; the second condition is that under the condition of T1 < T0 (including T1 < 0), at tl, the slope of Tair⑴ will change from positive to negative as shown in Figure 9; For all the conditions described above, no matter when the thermometer (t0 ... tn) withstands rapid temperature changes, the differential of Tair (t) (the slope of Tair⑴) can be known, the amplitude of the ambient temperature interference (T0 ... Τη) can also be solved from the mathematical formula (12). R r and r wg are used to replace r air. Both Tean (t) and Twg (t) can be solved from the formula (12). Tsen at non-uniform temperature The influence of the temperature difference between Tean, Tean and Twg on the accuracy of the thermometer and the compensation and calculation are discussed as follows: As mentioned above, infrared The temperature of the metal packaging tube wall (Tean (t)) and the waveguide 12 (Twg (t)) can be measured by the temperature reference sensor (such as the waveguide 12 and the infrared detector 11) near the optical system (such as The temperature (TaiJ〇) measured by the ambient temperature sensor 13) shown in Figure 1 is calculated. The time derivative (dTaK (t) / dt) and the known time constants I * ean and rwg are derived from the above experiments. First, consider the situation where there is a temperature difference between the waveguide 12 and the infrared sensor 1 1 1, as shown in FIG. 10, the infrared sensor Π 1 at a small tilted stereo angle dQ receives The energy of the self-luminous RA target 1 0 1 d〇) can be written as: άΦ = RA * cos (6r) * dQ (15) According to Stefan-Boltzmann's law: ΙΙΑ = (σΤΛ4 / π) dcP = (aTA4 / 7i ) * cos (0r) * dQ (16) ΪΒ1 — page 13 528862 The diagram briefly illustrates the internal cross-sectional view of the present invention, a door < ^ ^ < Cross-section view of infrared detector. Figure 2 is a block diagram of the program of the present invention. Figure 4 is the forward calculation of the present invention, ir M tone A-solid temperature sensor experimental test. Example sectional view of a temperature correction derived shoulder different method. also/

A graph of changes in ambient temperature to which the test examples are subjected. Γ 变 ί The temperature L measured by the three sensors in the experimental example of the experiment is shown in Figure 7. The slope of the rapid change of the plateau at different times. Figure 8 is the present invention; the experimental test example is subjected to two different loops, W Xu, and Tujia sections. Yi Xiong / Dian Du Xun Mi 増 Figure 9 is the actual curve of the present invention. Ambient temperature increases and decreases rapidly

Fig. 10 is used to calculate the graph when 々k A, · external line self-guided wave tube radiates different paths. DESCRIPTION OF SYMBOLS 1-Chassis II --- Infrared detector 13 Ambient temperature sensor 15 --- Display unit 4 THRwg 43 --- THRair III --- Infrared sensor 113 --- Metal packaging tube wall 12 —-Guide tube 14 --- Signal processing unit 31 --- Measured object 42 — THRcan 101 — — Target 112 Temperature reference sensor 114 — Base plate

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Claims (1)

528862 6. Scope of patent application 1 · An infrared-optical system-infrared detection collected infrared to perceive infrared-environment temperature-signal processing detector and environmental compensation value, use a display unit to maintain the ear with the above-mentioned compensation and then use it. The wire ear temperature snatch is used to receive the detector, and the wire can be converted into a line detector sensor unit. Its temperature sensing to eliminate the temperature is used to indicate that the compensation value is high. The temperature includes: The infrared of the patient's ear canal; an infrared sensor is provided to the electrical signals of the aforementioned optical system and a temperature of the substrate for the temperature reference sensor; to detect changes in the ambient temperature; collect the temperature from the infrared sensor and the reference temperature sensor The electrical signal has a one-degree change effect through an algorithm; and the temperature reading value; corrects the temperature reading value and changes the accuracy at a rapid temperature, so that the ear temperature can be kept constant. Page 18 528862 6. Scope of patent application 3. As for the infrared ear thermometer temperature compensation method described in item 2 of the scope of patent application, its algorithmic setting and use conditions are obtained through experimental tests based on actual conditions. Page 19