WO2003023342A1

WO2003023342A1 - Electronic thermometer

Info

Publication number: WO2003023342A1
Application number: PCT/EP2002/008491
Authority: WO
Inventors: Gert Michael Frank; Thomas Wilhelm Ernst Robst; Ronald G. Letourneau
Original assignee: Gme Rechte Und Beteiligungen Gmbh
Priority date: 2001-07-30
Filing date: 2002-07-30
Publication date: 2003-03-20

Abstract

An electronic thermometer includes a thermometer circuit (82), a probe (46), a display (18), and a power supply circuit (90). The power supply circuit (90) is connected to the thermometer circuit (82) to supply power to drive the thermometer circuit. The power supply circuit (90) includes a solar cell (20) and a capacitor (98) arranged such that a voltage at the solar cell (20) charges the capacitor (98) and the capacitor supplies the power to drive the thermometer circuit (82).

Description

Electronic Thermometer

BACKGROUND OF THE INVENTION

The present invention relates to electronic clinical thermometers. Clinical thermometers are thermometers of relatively high accuracy which are used in medical diagnosis and research. Such thermometers should be capable of measuring physiological temperatures with an accuracy of about 0.1°C, over an expected temperature range of about 34°C to 42°C. In practice, the actual temperature range may be broader or narrower. In the past, most clinical thermometers contained mercury as a ther- mometric fluid. However, mercury is quite toxic, and is rapidly being phased out. Thermometers of Galinstan^®, a liquid metal alloy of gallium, indium and tin have been available for several years now. However, these thermometers tend to be relatively expensive, and like mercury thermometers, can be readily broken. Unlike mercury thermometers, however, thermometers employing Galinstan thermometric fluid are non-toxic, and thus their use is steadily increasing.

Digital clinical thermometers have several advantages over classical liquid-filled thermometers, including easy reading, the ability to maintain a given reading for an extended time, and rapid and unambiguous reset. However, digital clinical thermometers have required a battery which re- suits in several drawbacks. First, the battery must be regularly replaced, and the thermometer cannot be used if a replacement battery is not available. Second, the disposal of batteries, even the more common zinc/manganese dioxide batteries, raises environmental concerns with regard to land filling with transition metal-containing waste. Digital thermometers employing solar cells have been used to monitor swimming pool temperatures. However, such devices are only operable in the light, and require a large surface area solar cell. Thermometers having a battery have additionally employed a solar cell to minimise the drain on the battery. However, such devices cannot operate on the solar cell alone, and the battery must still be replaced.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a solar-powered digital clinical thermometer that allows repeated temperature measurements, even in the dark, and does not contain an environmentally unfriendly battery.

The present invention meets this object by providing an electronic thermometer which comprises a housing, a thermometer circuit disposed in the housing, a probe, a display and a power supply circuit. The thermometer circuit determines a temperature at the probe and drives the display to indicate the temperature at the probe. The power supply circuit is connected to the thermometer circuit to supply power to drive the thermometer circuit. The power supply circuit includes a solar cell and a capacitor which are arranged such that the voltage at the solar cell charges the capacitor and the capacitor supplies the power to drive the thermometer circuit.

The capacitor may take many form and may be, for example, an electrolytic capacitor or a double layer capacitor. The capacitance of the capacitor is, preferably, at least 2,000 μF, more preferably, at least 4,000 μ-F, even more preferably, at least 10,000 μF. Most preferably, the capacitance is at least 20,000 μF.

In an embodiment of the present invention, an electronic thermometer in combination with a thermometer holder is provided. The holder is adapted to removably receive the thermometer. The holder may also com- prise a dispenser for dispensing probe covers.

In another embodiment, the present invention provides a holding device for a solar-powered thermometer, wherein the holding device is configured to allow the thermometer to sufficiently receive solar energy when held in the holding device. The holding device may comprise an elongated receiving body with inner and outer surfaces extending to a closed end and an opposite open end through which the thermometer is to be disposed. The inner surface is formed to complement the outer surface of the thermometer to receive a portion of the thermometer disposed through the open end. The inner sur- face is formed adjacent the open end to complement and receive the display when the thermometer is in the receiving body.

The electronic thermometer of the present invention allows repeated temperature measurements, even in the dark, and does not contain an environmentally unfriendly battery. The capacitor is charged from voltage at the solar cell and supplies the power to drive the thermometer circuit. The above and other objects, features, and advantages of the present invention are readily apparent from the following detailed description of the preferred embodiments when taken in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a top view of an electronic thermometer in accordance with an embodiment of the present invention;

Fig. 2 is a side view of the thermometer of Fig. 1 ;

Fig. 3 is a bottom view of the thermometer of Fig. 1; Fig. 4 is a cross-sectional side view of the thermometer of Fig. 1;

Fig. 5 illustrates the electronic thermometer in combination with a thermometer holder;

Fig. 6 illustrates the thermometer in combination with a thermometer holder that includes a probe cover dispenser; Fig. 7 is a diagram of the electronic circuitry of the thermometer;

Fig. 8 is a front view of a thermometer assembly depicting the electronic thermometer and a holding device therefor;

Fig. 9 is another front view of the holding device of Fig. 8;

Fig. 10 is a side view of the holding device of Fig. 8; Fig. 11 is another embodiment of the holding device;

Fig. 12 is a perspective view of yet another embodiment of the holding device;

Fig. 13 is a top view of the embodiment shown in Fig. 12; and

Fig. 14 is a side view of still another embodiment of the holding device.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In Figs. 1 to 3, an electronic thermometer made in accordance with the present invention is generally indicated at 10. The thermometer 10 includes a front housing 12, a rear housing 22, a bottom housing 26 and a sensor tip 14. A mask 16 covers and protects a liquid crystal display 18. A solar cell 20 charges an internal capacitor of a power supply circuit so that the capacitor may supply power to drive the thermometer circuit. Power is turned on by means of a push button switch 24.

The sectional view of Fig. 4 shows some of the internal components of the electronic thermometer 10 including a conductive rubber 30 adjacent the display 18 and a printed circuit board 32. A module holder 34 holds the display 18, the conductive rubber 30, and the printed circuit board 32. Contacts 36 and 38 may be pushed together into electrical contact when the push button 24 is asserted. A screw 40 holds the housing pieces together. The thermometer 10 is further provided with an internal buzzer 42 connected to the printed circuit board 32 by lead wires 44. A probe 46 disposed in the sensor tip 14 is also connected to the printed circuit board 32 by lead wires 48.

Fig. 5 illustrates a combination of the electronic thermometer 10 and a holder 52 adapted to removably receive the thermometer front housing 12. The holder 52 may be mounted, for example, on a bathroom wall or may be configured to stand up next to a user's night stand. It may be mounted with, for example, small screws or a double sided adhesive pad.

In Fig. 6, another combination is illustrated, which includes the elec- tronic thermometer 10 and a holder 62 adapted to removably receive the thermometer front housing 12. The holder 62 includes a dispenser for probe covers 64 which are dispensed one at a time by cooperation of an annular member 66, a seat 68, and a spring 70.

The holder 52, 62 of Figs. 5 and 6, respectively, may be mounted, for example, on a wall of an examination room in clinics and doctors' offices, as well as, on a wall in a patient room. The holders 52 and 62 are advantageous in that the electronic thermometer solar cell 20 is continuously exposed to ambient light.

In Fig. 7, a thermometer circuit 82 drives the liquid crystal display 18. The probe 46 and the push button switch 24 are connected to the thermometer circuit 82, which operates to sense the temperature at the probe 46 and display the reading on the display 18.

The thermometer circuit 82 to powered by a power supply circuit 90 which includes the solar cell 20 and a capacitor 98. The solar cell 20 and the capacitor 98 are arranged such that a voltage at the solar cell 20 charges the capacitor 98 and the capacitor 98 supplies the power to drive the thermometer circuit 82. When a voltage is present at the solar cell 20, diodes 94 and 96 provide charging current to the capacitor 98. There is no battery.

The thermometer of the present invention thus has the advantage of being able to take repeated temperature measurements, even in the dark, but does not have the disadvantage of containing an environmentally unfriendly battery because the capacitor 98 is utilised to store energy and power the thermometer circuit 82.

A suitable capacitor 98 for use in embodiments of the present invention is an electrolytic capacitor such as an aluminium electrolytic capacitor, or, preferably, a double layer capacitor. It is appreciated that higher capacitance of the capacitor 98 allows the thermometer circuit 82 to operate longer without a voltage at the solar cell 20. A preferred embodiment of the present invention utilises a 22,000 μF double layer capacitor.

Fig. 8 illustrates an electronic thermometer assembly 110 including a holding device 112 and an electronic thermometer 10 being held therein. As shown, the holding device 112 has closed and opened ends 114, 116, respectively. The thermometer 10 is inserted through the open end 116. Preferably, the thermometer 10 fits snugly in holding device 112. The thermometer 10 has an outer surface 119 on which the solar cell 20 and the display 18 are disposed.

The display 18 includes a magnifying lens which convexly protrudes outward from the outer surface 119. As depicted in Fig. 8, the sensor tip 14 of the thermometer 10 is inserted through the open end 116 to allow the display 18 to be held in holding device 112 with a snug fit. Formed on the holding device 112 is a slot 124 to receive the display 18. Thus, when the thermometer 10 is disposed within the holding device 112, the display 18 and the sensor tip 14 are protected by the holding device 112, while allowing the solar cell 20 to be exposed to light to allow solar energy to be received therethrough. As shown in Figs. 9 and 10, the holding device 112 comprises an elongated receiving body 128 which includes an inner surface 130 and an outer surface 132, wherein the surfaces 130, 132 have a front wall 134 and a rear wall 136 integrally connected by side walls 138, 140. The receiving body 128 has a pair of first and second ends, wherein the first end has a bottom wall 142 integrally connecting the front and rear walls 134, 136 to define the closed end 114. The inner surface 130 complements the outer surface 119 of the thermometer 10 to receive a portion of the outer surface 119. The front wall 134 of the inner surface 130 is concavely formed to define the slot 124 to complement and receive the display 18 which is convexly formed relative to the outer surface 119. The holding device 112 is configured to allow the solar cell 20 of the thermometer 10 to receive solar energy for powering the thermometer 10 when held therein. This is accomplished by forming the receiving body 128 so as to avoid overlap of the solar cell 20, allowing exposure of the solar cell 20 to receive solar energy therethrough when the thermometer 10 is in the holding device 112.

In this embodiment, the inner surface 130 has a length L which allows the receiving body 128 to receive a first portion P of the thermometer 10 without overlapping or covering the solar cell 20. In use, the thermometer 10, as held in the receiving body 128, has exposed a second portion X which may be handled by a user for easy removal of the thermometer 10 from the receiving body 128. The receiving body 128 may have a length greater than L, but is formed to permit exposure of the solar cell 20. Moreover, in this embodiment, the rear wall 136 includes a support 148 extending from the open end 116 to provide added support in holding the thermometer 10 in the receiving body 128. In this embodiment, the receiving body 128 is tapered from its open end 116 to its closed end 114.

As shown in Fig. 10, the holding device 112 may include mounting means thereon to mount the holding device 112 onto a surface. For example, as shown in Fig. 10, a pressure sensitive adhesive 144 may be attached to the rear wall 136. Any suitable pressure sensitive adhesive may be used. Thus, in use, the adhesive 144 may be mounted onto a rigid surface. As also shown, the front wall 134 of the outer surface 132 is formed convexly to complement the slot 124 of the inner surface 130, allowing the display 18 of the thermometer 10 to fit snugly in the holding device 112. Thus, the front wall 134 convexly protrudes from the outer surface 132.

Fig. 11 depicts another mechanism for mounting the holding device 162 onto a surface. As shown in Fig. 11, the holding device 162 may be mounted onto a surface 164 by screws 166. In this embodiment, the rear wall 176 may have apertures (not shown) to allow the screws 166 to be disposed therethrough and attached onto the surface 164. Other suitable means such as rivets may be used for attaching the holding device 162 onto a surface.

It is to be noted that such mounting means include means which at- tach the holding device 112, 162 to a surface which would not hinder the solar cell 20 of the thermometer 10 from receiving solar energy when inserted in the holding device. Although not wanting to limit the time during which the mounting means attach the holding device to a surface, such mounting means is configured to attach the holding device to a surface for up to a peπnanent time period and not only a temporary time period. Fig. 12 depicts a holding device 212 which comprises a receiving body

228 having a bottom portion 214 attached to a foot 231. The receiving body 228 includes similar elements as the receiving body 128 of the embodiment describe above. The foot 231 inserts into a groove 233 formed on a base 235. The base 235 is shown to be a circular body, but may take on any other suit- able shape so long as the foot 231 may be inserted into the groove 233 to attach the receiving body 228 thereto. Preferably, the base 235 is mounted by any suitable means to a surface, such as a counter top. In use, the foot 231, which is integrally attached to the receiving body 228, is inserted in the groove 233 to hold the receiving body 228 at an angle sufficient to allow the solar cell of the thermometer to receive solar energy. Thus, the receiving body 228 is held at an angle such that the thermometer 10, when disposed therein, may receive energy through the solar cell 20.

In yet another embodiment, a thermometer assembly 310 depicted in Fig. 14 includes a holding device 312, an electronic thermometer 10 inserted in the holding device 312, and a light bulb 315 attached to the holding device 312. As shown, the assembly 310 is configured to be used as a night light attachable to an electrical outlet which, when powered, allows the light bulb 315 to emit light. In turn, the thermometer 10 disposed in the holding device 312 may receive solar energy emitted from the light bulb 315 when the hold- ing device 312 is plugged into an electrical outlet. In use, the assembly 310 serves as a night light and a recharger for the electronic thermometer 10.

As shown in Fig. 14, the holding device 312 includes an electrical socket 318 formed sufficiently adjacent an open end 316 so that when the light bulb 315 is in electrical contact with the socket 318, energy emitted the from bulb 315 is received by the solar cell 20 of the thermometer 10 inserted in the holding device 312. The holding device 312 further includes a plug 331 which extends from a rear wall 336 of the receiving body 328. As shown, the plug 331 is attachable to an electrical socket (not shown). The plug 331 is configured to be in electrical communication with the socket 318 to provide electrical power thereto when a light bulb 315 is in electrical contact with the socket 318, thereby, recharging the thermometer 10.

Claims

1. An electronic thermometer comprising: a temperature sensing probe (46); a thermometer circuit (82) connected to the probe (46); a display driven by the thermometer circuit (82) to indicate the temperature at the probe (46); and a power supply circuit (90) including a solar cell (20) for supplying power to the thermometer circuit (82), characterised in that the power supply circuit (90) includes a capacitor (98) adapted to be charged by the solar cell (20) .

2. The electronic thermometer of claim 1 wherein the capacitor (98) is an electrolytic capacitor or a double layer capacitor.

3. The electronic thermometer of claim 1 or 2 wherein the capacitor (98) has a capacitance of at least 2,000 μF, preferably at least 4,000 μF, more preferably at least 10,000 μF, and still more preferably at least 20,000 μF.

4. A combination of the thermometer (10) of any preceding claim with a holder (52, 62, 112, 162, 212, 312) adapted to removably receive the thermometer.

5. The combination of claim 4 wherein the holder (62) comprises a dispenser (66, 68, 70)for dispensing probe covers (64).

6. The combination of claim 4 wherein the holder (52, 62, 112, 162, 212, 312) is configured so that the solar cell (20) is exposed to ambient light when the thermometer (10) is in the holder.

7. The combination of claim 6 wherein the holder (312) includes a light source (315) arranged to illuminate the solar cell (20) when the thermometer (10) is in the holder.