Probe structure

The present invention discloses an improved probe structure, which is installed in the body of an infrared clinical thermometer and comprises a plastic hollow casing having an opening; a curved block annularly arranged inside the opening; a hollow sleeve arranged inside the casing and along the perimeter of the opening; a temperature sensor arranged inside sleeve and below the curved block; a support element arranged inside the sleeve and supporting the temperature sensor; and a thermal insulation ring encircling the temperature sensor and pressing against the inner wall of the sleeve. The thermal insulation ring has an outer diameter larger than a width of the temperature sensor, and an air gap is thus formed between the temperature sensor and the inner wall of the sleeve; the top of the thermal insulation ring has an altitude higher than the top of the temperature sensor, and another air gap is thus formed between the temperature sensor and the curved block. Thereby is effectively retarded heat conduction from the external to the temperature sensor.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an improved probe structure, particularly to an improve probe structure, which can effectively separate the probe from the external heat source.

2. Description of the Related Art

The ear thermometer detects the infrared rays radiated by the eardrum to learn the body temperature. The eardrum is located inside the skull and near the hypothalamus—the temperature control center of the body. As the carotid fully supplies blood to the eardrum, the eardrum can promptly reflect the central temperature variation of the body. The ear temperature can be used to calculate the oral temperature and rectal temperature for clinic reference. As the ear thermometer can rapidly output temperature accurately and is easy to operate, it has been the mainstream instrument for body temperature measurement.

Generally, isolating the ear thermometer from the influence of external heat can effectively increase the accuracy thereof. Therefore, there are many designs to achieve the function. Refer to FIG. 1 for a U.S. Pat. No. 4,636,091. In the prior art, the sensor10is arranged inside a low-conductivity plastic sleeve12, and a high-conductivity casing14separates the plastic sleeve12from the environment. The bottom of the sensor10contacts a cast piece16made of a high-conductivity ceramic material, and the cast piece16can fast conduct from the sensor10the heat caused by radiation. The prior-art patent uses the plastic sleeve12to separate the sensor10from the external heat conducted by the casing14. Refer toFIG. 2. In the abovementioned design, electric capacity may simulate thermal capacity, and electric resistance may simulate thermal resistance. Thus, the path via which the external heat is conducted to the sensor10may be regarded as that the external heat sequentially passes through the casing14simulated by an electric capacitor18, the plastic sleeve12simulated by an electric resistor20, the cast piece16simulated by an electric capacitor16, and a metallic sensor housing (not shown in the drawing) simulated by an electric capacitor22.

Refer to FIG. 3 for a U.S. Pat. No. 5,018,872. In the prior art, the probe structure comprises a plastic hose24, a metallic shelter26arranged inside the plastic hose24, a sensor28arranged inside the metallic shelter26, and a radiator30contacting the bottom of the sensor28to fast dissipate the heat passing through the plastic hose24and reaching the metallic shelter28. Refer toFIG. 3. In the design, electric capacity may also simulate thermal capacity, and electric resistance may also simulate thermal resistance. Thus, the path via which the external heat is conducted to the sensor28may be regarded as that the external heat sequentially passes through the plastic hose24simulated by an electric resistor32, the radiator30simulated by an electric capacitor34, and the metallic shelter26simulated by an electric capacitor36.

Refer to FIG. 5 for a U.S. Pat. No. 5,874,736. In the prior art, the path via which the external heat is conducted to the sensor38may be regarded as that the external heat sequentially passes through an electric resistance (simulating the sleeve40), an electric capacitor (simulating the radiator42), and an electric capacitor (simulating a flange44in the rear of the metallic encapsulating casing of the sensor38). In a U.S. Pat. No. 6,743,346, the external heat is conducted to the sensor via a path of an electric resistance (a sleeve), an electric capacitor (a radiator), and an electric capacitor (a metallic encapsulating casing of the sensor).

The abovementioned prior-art patents respectively use different structures to retard the heat conducted from the external to the sensor. However, they all have the same mode-one electric resistor together with several electric capacitors. Therefore, the abovementioned prior-art patents have about identical effect in separating the sensor from the influence of external heat.

Accordingly, the present invention proposes an improved probe structure to effectively solve the problems of the conventional probe stricture.

SUMMARY OF THE INVENTION

The primary objective of the present invention is to provide an improved probe structure, which uses a thermal-insulation ring to effectively reduce the influence of external heat on infrared detection and greatly promote the accuracy of an ear thermometer.

Another objective of the present invention is to provide an improved probe structure, wherein a curved block is arranged inside the opening of the probe to control the detection angle of the temperature sensor and promote the accuracy of temperature measurement.

To achieve the abovementioned objectives, the present invention proposes an improved probe structure, which is installed in the body of an infrared clinical thermometer and comprises a plastic hollow casing having an opening; a curved block annularly arranged inside the opening; a hollow sleeve arranged inside the casing and along a perimeter of the opening; a temperature sensor arranged inside sleeve and below the curved block; a support element arranged inside the sleeve and supporting the temperature sensor; and a thermal insulation ring encircling the temperature sensor and pressing against an inner wall of the sleeve. The thermal insulation ring has an outer diameter larger than a width of the temperature sensor, and a first air gap is thus formed between the temperature sensor and the inner wall of the sleeve; the top of the thermal insulation ring has an altitude higher than the top of the temperature sensor, and a second air gap is thus formed between the temperature sensor and the curved block.

Below, the embodiments are described in detail to make easily understood the objectives, technical contents, characteristics and accomplishments of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention proposes an improved probe structure, which is installed in the body of an infrared clinical thermometer, such as a forehead thermometer or an ear thermometer, to promote the accuracy of temperature measurement.

Refer toFIG. 6andFIG. 7respectively a sectional view and a partially enlarged view schematically showing an improved probe structure according to one embodiment of the present invention. The improved probe structure of the present invention comprises a plastic casing50with an opening52; a metallic sleeve54arranged inside the plastic casing50and along the inner rim of the opening52, wherein a gap56is formed between the plastic casing50and the metallic sleeve54to increase the thermal insulation; a curved block58arranged along the inner rim of the top of the metallic sleeve54, having a curvature of about 30-85 degrees, and plated with a coating59to increase reflectivity and decrease infrared radiation, wherein the curved block58and the metallic sleeve54are fabricated into a one-piece component; a support element60arranged inside the metallic sleeve54, wherein the support element60may be a round tube; a temperature sensor62arranged on the top of the support element60and including a thermocouple63and an encapsulation base65sustaining the thermocouple63, wherein the support element60supports the temperature sensor62to exist between the support element60and the curved block58, and the curved block58thus encircles the top surface of the temperature sensor62; a thermal insulation ring64encircling the temperature sensor62and pressing against the inner wall of the metallic sleeve54, wherein the thermal insulation ring64has an outer diameter a greater than the width b of the temperature sensor62, and an air gap66is thus formed between the temperature sensor62and the inner wall of the metallic sleeve54, and wherein the top of the thermal insulation ring64has an altitude higher than the top of the temperature sensor62, and an air gap68is thus formed between the temperature sensor62and the curved block58.

Refer toFIG. 8. When intending to use the ear thermometer to measure the body temperature, the user inserts the probe structure into his ear. The temperature sensor62receives infrared rays, wherein the coating59on the curved block58retards or reflects the infrared rays having too large a scattering angle and concentrates other infrared rays on the temperature sensor62to reduce the interference of temperature noise and increase the accuracy of temperature measurement.

Refer toFIG. 9for an equivalent circuit of a path via which external heat is conducted to the temperature sensor in the improved probe structure according to one embodiment of the present invention. In the improved probe structure of the present invention, external heat is conducted to the temperature sensor62via a path of the low-thermal conductivity plastic casing50(simulated by an electric resistor70), the metallic sleeve54(simulated by an electric capacitor72), the thermal insulation ring64(simulated by an electric resistor74), and a sensor encapsulation housing (simulated by an electric capacitor76). Thereby, the present invention can more effectively separate the temperature sensor from the interference of external heat than the conventional technology. Thus, the present invention can greatly promote the accuracy of temperature measurement of an ear thermometer.

In the present invention, a curved block is arranged inside the opening of the probe to decrease the detection angle to more precisely detect the eardrum temperature and obtain a higher-accuracy temperature measurement result. As the curved block can decrease the sensitivity of the temperature sensor to heat conduction, the gap between the casing and the temperature sensor can be decreased to reduce the volume of the probe structure. Besides, a thermal insulation ring is used to retard the conduction of external heat to the temperature sensor and reduce the influence of external heat on infrared detection, which further promotes the accuracy of temperature measurement of an ear thermometer.