EP3339981B1 - Watch provided with a thermoelectric push button - Google Patents

Description

Field of the invention

The invention relates to an apparatus (for example a watch, a telephone, a remote control, etc.) provided with an actuating system for activating an electrical element of said apparatus (the electrical element is for example an LED , an electromagnetic wave transmission antenna, timing means, etc.).

Background of the invention

It is known to activate an electrical element of a device by operating a push button. For example, it is known to activate means of lighting the dial of a watch by actuating a push button located outside the middle part, to activate a transmitting antenna of a remote control via a button of the remote control, for example to control an audiovisual apparatus or a luminaire. Actuation of the push button causes the establishment of an electrical contact between a power source (generally a battery) and the electrical element (a light source, generally a light emitting diode, an infrared or radio frequency optical transmission element, etc.).

This system, however, requires the use of a source of exhaustible electrical energy (the battery). EP 1 227 375 A1 relates to a timepiece generating thermoelectric energy comprising a dial, a movement and a thermal conduction sheet, provided in an enclosed space, defined by a metal case, with a glass attached thereto, and a bottom and further comprising a thermoelectric element housed in a space between the thermal conduction sheet and the bottom of the housing. The bottom is made of two types of materials each having a different thermal conductivity. FR 2 310 589 A1 relates to an electric wristwatch comprising a "housing, a display device, a timekeeping module, an electrical energy storage device and a thermoelectric generator, comprising at least two parts thermally insulated from one another connected to the thermoelectric generator, these parts being arranged so that their temperature levels are at least temporarily different.

Summary of the invention

The object of the present invention is to overcome the drawback mentioned above.

• un boîtier présentant une cavité ouverte vers l'extérieur du boîtier
• un élément électrique disposé à l'intérieur du boitier
• un système d'actionnement de l'élément électrique, comprenant :
  • ∘ un module thermoélectrique comportant une première plaque et une deuxième plaque électriquement isolantes, sensiblement parallèles l'une à l'autre et portant des dominos électriquement conducteurs, et des piliers semi-conducteurs s'étendant entre les dominos de la première plaque et les dominos de la deuxième plaque, le module thermoélectrique étant logé dans la cavité de sorte que la deuxième plaque est disposée contre des parois de la cavité et la première plaque est accessible depuis l'extérieur du boîtier
  • ∘ un circuit électronique de transmission reliant deux dominos de la deuxième plaque à l'élément électrique.

For this purpose, the invention relates to an apparatus comprising:

• a housing having a cavity open towards the outside of the housing
• an electrical element disposed inside the housing
• an actuation system of the electric element, comprising:
  • ∘ a thermoelectric module comprising a first plate and a second electrically insulating plate, substantially parallel to one another and carrying electrically conductive dominoes, and semiconductor pillars extending between the dominoes of the first plate and the dominoes of the second plate, the thermoelectric module being housed in the cavity so that the second plate is disposed against walls of the cavity and the first plate is accessible from outside the housing
  • ∘ an electronic transmission circuit connecting two dominoes of the second plate to the electrical element.

The first plate is initially at the environmental temperature of the apparatus, and the second plate is initially at the temperature of the housing since it is positioned against a wall of the cavity of the housing. When the first plate is heated, for example by transmitting the natural heat released by a finger placed on the first plate, by friction of the finger on the first plate, or by actuating an intermediate plate which itself comes to create friction on the first plate, there is a temperature difference between the first and the second plate. The temperature gradient is at the origin of an electric potential difference via the Seebeck effect between the dominoes of the first plate and the dominoes of the second plate. This difference in electrical potential is then communicated to the electrical element via the electronic transmission circuit. The actuation system behaves like a thermoelectric push button without moving part, perfectly sealed, and used for both mechanical watches and electronic watches.

It is noted that using a converter placed at the output of the thermoelectric element and capable of converting voltages of the order of one millivolt to volt volt voltages, if the apparatus is in an environment at a temperature lower than that of the human body, a simple contact of the finger on the first plate is sufficient to generate sufficient electrical power to produce visible light using a light emitting diode. On the other hand, if the device is worn on the body or is in an environment at a temperature higher than that of the human body, it is necessary to rub the first plate to generate such power.

According to advantageous embodiments of the invention, the apparatus may have the following characteristics, taken alone or in any technically possible combination.

In a non-limiting embodiment, the first plate is constituted or comprises a layer made of a material with a high coefficient of friction.

In a non-limiting embodiment, the electronic transmission circuit comprises a DC-DC converter and two electrical son passing through the housing, each wire being connected on the one hand to a domino of the second plate and on the other hand to said converter.

In a non-limiting embodiment, the electronic transmission circuit comprises an accumulator placed at the output of the DC-DC converter, and a control unit connected on the one hand to the battery and on the other hand to the electric element, to discharge the battery when its charge exceeds a threshold value.

In a non-limiting embodiment, the accumulator is a capacitor.

In a non-limiting embodiment, the actuation system comprises an electrical insulating layer disposed between the first plate and the second plate and laterally covering the thermoelectric module.

In a non-limiting embodiment, the actuating system comprises an intermediate plate and means for moving the intermediate plate against the first plate.

In a non-limiting embodiment, the apparatus is a wristwatch.

In a non-limiting embodiment, the device is a remote control.

In a non-limiting embodiment, the apparatus is a wireless wall switch.

In a non-limiting embodiment, the electrical element comprises a light-emitting diode.

In a non-limiting embodiment, the electrical element comprises a radiofrequency transmitter.

Brief description of the drawings

• La figure 1 est un schéma de principe d'un bouton poussoir thermoélectrique porté par une montre selon un mode de réalisation de l'invention.
• La figure 2 est une vue de côté de la montre de la figure 1.
• La figure 3 est une représentation schématique du poussoir thermoélectrique de la figure 1.
• La figure 4 est une représentation schématique d'un circuit électronique de transmission faisant partie du poussoir thermoélectrique de la figure 1.

Other particularities and advantages will emerge clearly from the description which is given hereinafter, by way of indication and in no way limiting, with reference to the appended drawings, in which:

• The figure 1 is a block diagram of a thermoelectric push button carried by a watch according to one embodiment of the invention.
• The figure 2 is a side view of the watch from the figure 1 .
• The figure 3 is a schematic representation of the thermoelectric pusher of the figure 1 .
• The figure 4 is a schematic representation of an electronic transmission circuit forming part of the thermoelectric pusher of the figure 1 .

Detailed Description of the Preferred Embodiments

The figure 1 illustrates an AP apparatus, which in this case is a wristwatch. Of course, the AP apparatus is not necessarily a watch, but could be another type of apparatus, for example a telephone, a remote control, or a wireless wall switch. The AP watch has a BT box inside which is an electric element EL (shown in FIG. figure 4 ). The electrical element EL is for example a light-emitting diode or a set of light-emitting diodes for illuminating the dial of the watch, or a radiofrequency transmitter. In a non-limiting embodiment, the electrical element consists of a set of diodes, each diode being placed at an hour index. Of course, the electric element EL is not necessarily a diode or a set of diodes. The electrical element EL is more generally any means of activating a function, switching on a mode, etc.

• un module thermoélectrique MT positionné par exemple sur une zone latérale du boitier BT, à l'emplacement classique d'un bouton poussoir
• un circuit électrique de transmission CT, traversant le boitier BT et reliant le module thermoélectrique MT à l'élément électrique EL.

The AP watch has an actuation system SA (shown in FIG. figure 4 ) of the electric element EL, also called thermoelectric push button, a part P1 is visible on the Figures 1 and 2 . As shown in detail in the figure 3 , the actuation system SA comprises:

• a thermoelectric module MT positioned for example on a lateral zone of the box BT, in the classic location of a push button
• an electrical transmission circuit CT, passing through the LV box and connecting the thermoelectric module MT to the electric element EL.

The thermoelectric module MT is positioned in a cavity CV made in the lateral zone of the housing BT and opening towards the outside of the BT box, that is to say the outer part of the AP watch. In known and conventional manner, the thermoelectric module MT comprises a first plate P1 and a second electrically insulating plate P2. The first plate P1 carries a plurality of electrically conductive SM dominoes arranged next to one another. Similarly, the second plate P2 carries a plurality of electrically conductive SM dominoes arranged next to each other. Each domino of the first plate P1 is connected to two dominoes of the second plate P2 by a pair of semiconductor PL pillars so as to make the best use of the Seebeck effect. Each pair of pillars PL has an n-doped semiconductor and a p-doped semiconductor. The first plate P1 and the second plate P2 extend substantially parallel to each other, and the pillars PL extend substantially orthogonally to the plates P1, P2.

The second plate P2 constituting the cold pole of the thermoelectric module MT is positioned against the bottom FD of the cavity CV. The first plate P1, facing the second plate P2, is therefore accessible from outside the BT box. The first plate P1 constitutes the hot pole of the thermoelectric module MT. Applying a temperature gradient across the thermoelectric module, by heating the first plate P1, causes the diffusion of charge carriers to the second plate P2, thereby generating an electrical voltage. The actuation system SA also comprises a thermal insulation layer IS disposed around the thermoelectric module MT, between the first and the second plate P1, P2.

The first plate P1 is for example heated by rubbing the finger, as shown in FIG. figure 1 . The first plate P1 is then advantageously constituted or covered with a material with a high coefficient of friction. However, in cases where the watch is in a sufficiently cold environment, a simple contact of the finger on the first plate P1 may be sufficient to create a sufficient temperature gradient to generate a voltage of a few millivolts at the output of the thermoelectric module MT.

In an alternative embodiment, the actuating system SA comprises an intermediate plate and means for moving the intermediate plate against the first plate P1, for example springs. A user does not have to touch or rub the first plate P1, which has a high coefficient of friction and is therefore not pleasant to the touch, but only to move the intermediate plate which itself rubs against the first plate P1. The intermediate plate is advantageously made of a material pleasant to the touch, for a better comfort of use.

• deux fils électriques F1, F2 connectés à deux dominos SM de la deuxième plaque P2 tels que les piliers PL semi-conducteurs sont en série entre ces deux dominos. Ces deux dominos constituent des bornes électriques. Les fils électriques F1, F2 traversent le boitier.
• un convertisseur continu-continu CC branché entre lesdits deux fils F1, F2 et disposé à l'intérieur du boîtier BT, pour augmenter la tension électrique générée par le module thermoélectrique MT. Typiquement, le convertisseur continu-continu CC est configuré pour convertir des tensions de l'ordre du millivolt en des tensions de l'ordre du volt.
• un accumulateur CD, dans le cas présent un simple condensateur tampon mais ce mode de réalisation n'est pas limitatif, en sortie du convertisseur continu-continu CC,
• une unité de contrôle UC pour décharger l'accumulateur CD lorsque sa charge dépasse une valeur seuil, le courant délivré par décharge de l'accumulateur CD étant fourni à l'élément électrique EL pour l'alimenter.

With reference to the figure 4 the transmission electronic circuit CT comprises:

• two F1, F2 electric wires connected to two SM dominoes of the second plate P2 such as the PL semiconductor pillars are in series between these two dominoes. These two dominoes constitute electrical terminals. The F1, F2 electrical wires pass through the case.
• a DC-DC converter connected between said two son F1, F2 and disposed inside the LV housing, to increase the voltage generated by the thermoelectric module MT. Typically, the DC-DC converter is configured to convert voltages of the order of one millivolt into voltages of the order of one volt.
• a CD accumulator, in this case a simple buffer capacitor but this embodiment is not limiting, at the output of the DC-DC converter,
• a control unit UC for discharging the CD accumulator when its load exceeds a threshold value, the current delivered by discharge of the CD accumulator being supplied to the electric element EL to supply it.

Of course, the present invention is not limited to the illustrated example but is susceptible of various variations and modifications that will occur to those skilled in the art.

Claims (12)

1. Device (AP) comprising:

   - a housing (BT) having a cavity (CV) that is open to the exterior of the housing (BT)

   - an electrical element (EL) positioned inside the housing (BT)

   - an actuation system (SA) for actuating the electrical element (EL), comprising:

   ∘ a thermoelectric module (MT) including first (P1) and second (P2) electrically insulating plates, which plates are substantially parallel to one another and bear electrically conductive terminal blocks (SM), and semiconductive pillars (PL) that extend between the terminal blocks of the first plate and the terminal blocks of the second plate, the thermoelectric module (MT) being housed inside the cavity (CV) such that the second plate (P2) is positioned against walls (FD) of the cavity (CV) and the first plate (P1) is accessible from outside the housing (BT)

   ∘ an electronic transmission circuit (CT) linking two terminal blocks (SM) of the second plate (P2) to the electrical element (EL).
2. Device (AP) according to the preceding claim, in which the first plate (P1) consists of or includes a layer consisting of a material having a high coefficient of friction.
3. Device (AP) according to one of the preceding claims, in which the electronic transmission circuit (CT) includes a DC-to-DC converter (CC) and two electrical wires (F1, F2) passing through the housing (BT), each wire being linked both to a terminal block (SM) of the second plate (P2) and to said converter (CC).
4. Device (AP) according to the preceding claim, in which the electronic transmission circuit (CT) includes an accumulator (CD) that is placed at the output of the DC-to-DC converter (CC), and a control unit (UC) that is connected both to the accumulator (CD) and to the electrical element (EL) for the purpose of discharging the accumulator (CD) when its charge exceeds a threshold value.
5. Device (AP) according to the preceding claim, in which the accumulator (CD) is a capacitor.
6. Device (AP) according to one of the preceding claims, in which the actuation system (SA) includes an electrical insulator layer (IS) that is positioned between the first plate (P1) and the second plate (P2) and laterally covers the thermoelectric module (MT).
7. Device (AP) according to one of the preceding claims, in which the actuation system (SA) includes an intermediate plate and means for moving the intermediate plate against the first plate (P1).
8. Device (AP) according to one of the preceding claims, characterized in that it is a wristwatch.
9. Device (AP) according to one of the preceding claims, characterized in that it is a remote control.
10. Device (AP) according to one of the preceding claims, characterized in that it is a wireless wall switch.
11. Device (AP) according to one of the preceding claims, characterized in that the electrical element (EL) includes a light-emitting diode.
12. Device (AP) according to one of the preceding claims, characterized in that the electrical element (EL) includes a radiofrequency transmitter.

Images