EP1752841A1 - Electronic watch which is brought to a stand-by condition according to a signal by an accelerometer - Google Patents

Abstract

The watch has a case (12) with an electronic control circuit (14) and analog/digital display units (16). The circuit, in an active operation mode of the watch, controls the display of the current hour. The circuit, in a standby operation mode of the watch, controls the stop of the units (16). The circuit triggers the passage from one mode to another based on a signal produced by an accelerometer (30) placed in the case. The accelerometer has pins for measuring the acceleration undergone by the watch, so that the circuit can determine if the watch is carried, in order to pass into active mode. The analog/digital display units (16) are supplied with electric power by an accumulator/battery (18). The accelerometer (30) has a microstructure formed by micromachining in a plate made of crystalline material.

Description

The present invention relates to an electronic watch having a sleep mode.

More particularly, the electronic watch according to the present invention is of the type comprising a housing containing an electronic control circuit and display means supplied with electrical energy by an accumulator or a battery, the watch comprising an active mode of operation, in which the electronic circuit controls the display of the current time by the display means, and a standby operating mode, in which the electronic circuit controls the stopping of the display means, the electronic circuit triggering the passage of a mode of operation to another depending on the signal produced by a sensor.

A watch of this type is described for example in the document EP 0 657 793 A a radio-controlled electronic watch having means for receiving a radio signal, a photoelectric sensor, and a liquid crystal display screen. According to this document, in view of the high energy consumption of the radio reception means, there is provided a standby mode for minimizing the consumption of electrical energy and consisting in stopping the receiving means and turning off the display screen . The watch changes from standby mode to active mode when a watch pushbutton is pressed or when the sensor detects light. The watch changes from active mode to standby mode when no pusher pressure has been detected for ten days or when no light has been detected by the sensor for ten days.

The system for triggering the standby mode and the active mode according to this document is not completely satisfactory because it mainly takes into account the lighting environment surrounding the watch. However, the watch can be placed in a place exposed to light without being used so far. This is why this watch must take into account, in addition to the signal provided by the sensor, an additional parameter constituted by the pressure on a pusher. The trigger system according to this document is therefore mainly adapted to a long-term storage of the watch.

Note that the use of a photoelectric sensor is detrimental to the appearance of the watch and the compactness thereof.

The present invention aims to overcome these disadvantages by providing a watch with a simpler and more effective trigger system.

For this purpose, the invention proposes a watch of the type described above, characterized in that the sensor is constituted by an accelerometer which is arranged inside the housing and which comprises at least one axis of measurement of the acceleration experienced by the watch, so that the electronic circuit can determine if the watch is worn, to switch to active mode.

The electronic circuit according to the invention has the advantage of actually taking into account the fact that the watch is worn by the user or not to trigger the transition from one mode of operation to another, which allows him to maximize savings. of electrical energy. In particular, the electronic circuit according to the invention is particularly responsive which allows it to go into standby mode as soon as the watch is no longer worn.

In addition, the electronic circuit according to the invention requires a single detection means to trigger the transition from one mode of operation to another. For example, the accelerometer makes it possible to detect the use of the watch before the user presses a pusher, by measuring the acceleration applied to the watch by the user when he grasps it.

According to an advantageous characteristic, the accelerometer comprises several axes for measuring the acceleration so as to detect any acceleration experienced by the watch, including when this acceleration does not have a component along one of the axes.

According to another advantageous characteristic, the accelerometer is constituted by a microstructure produced by micromachining in a plate of crystalline material, which facilitates its integration into the electronic circuit. In particular, when the electronic control circuit comprises an integrated circuit board, the accelerometer can be mounted directly on the wafer, along with the other components. In addition, the cost of this type of accelerometer is particularly interesting.

• la montre comporte un organe de commande qui permet de déclencher manuellement le passage d'un mode de fonctionnement à l'autre ;
• le circuit électronique commande la montre en mode veille lorsque aucune accélération n'a été mesurée pendant une durée déterminée ;
• les moyens d'affichage sont du type analogique ;
• le circuit électronique comporte des moyens pour mémoriser la position occupée par les moyens d'affichage analogiques au moment de leur arrêt ;
• les moyens d'affichage sont du type digital.

According to other features of the invention:

• the watch comprises a control member which makes it possible to manually trigger the transition from one mode of operation to another;
• the electronic circuit controls the watch in standby mode when no acceleration has been measured for a given period;
• the display means are of the analog type;
• the electronic circuit comprises means for storing the position occupied by the analog display means at the time of their stop;
• the display means are of the digital type.

• la figure 1 est une vue en coupe axiale qui représente schématiquement une montre électronique conforme aux enseignements de l'invention ;
• la figure 2 est un diagramme qui représente schématiquement le circuit électronique équipant la montre de la figure 1.

Other features and advantages of the present invention will appear more clearly on reading the detailed description which follows, made with reference to the accompanying drawings given by way of non-limiting example and in which:

• Figure 1 is an axial sectional view which schematically shows an electronic watch according to the teachings of the invention;
• FIG. 2 is a diagram which schematically represents the electronic circuit equipping the watch of FIG. 1.

In Figure 1, there is shown an electronic watch 10 made according to the teachings of the invention. It comprises a housing 12 containing an electronic control circuit 14 and display means 16 supplied with electrical energy by an accumulator or a battery 18.

According to the embodiment shown, the display means 16 are of the analog type and consist of at least two needles 20, 22 driven in rotation by an electric motor 24.

Of course, according to an alternative embodiment (not shown), the display means 16 may be of the digital type and include a liquid crystal screen.

The electronic circuit 14 is here arranged on an integrated circuit board 25 fixed in the housing 12 and it comprises a microcontroller 26 which controls the display means 16 so as to display the current time according to a given time base. by a time division circuit 28 comprising a resonator.

The watch 10 comprises an active operating mode, in which the electronic circuit 14 controls the display of the current time by the display means 16, and a standby operating mode, in which the electronic circuit 14 controls the stop display means 16. The electronic circuit 14 triggers the passage from one operating mode to another depending on the signal produced by a sensor 30.

According to the teachings of the invention, the sensor 30 is constituted by an accelerometer 30 which is arranged inside the housing 12 and which comprises at least one measurement axis of the acceleration experienced by the watch 10, so that the electronic circuit 14 can determine if the watch 10 is worn, to go into active mode.

The accelerometer 30 produces analog electrical signals representative of the instantaneous acceleration experienced by the watch 10. These signals pass through an analog-digital converter 32 before being input to the microcontroller 26, in the form of a digital signal .

Note that the accelerometer 30 may comprise several axes for measuring the acceleration, for example along two orthogonal axes, so as to detect any acceleration experienced by the watch 10, including when this acceleration does not have a component along one of the axes.

Advantageously, the accelerometer 30 is constituted by a microstructure produced by micromachining in a plate of crystalline material such as silicon. The accelerometer 30 is therefore in the form of a microcircuit which is mounted directly on the wafer 25 with integrated circuits.

The accelerometer 30 is of conventional type and the skilled person will not encounter any particular difficulty to choose one that is suitable for the implementation of the present invention.

According to an advantageous embodiment, the watch 10 comprises a control member 34 such as a push button that can manually trigger the switch from one operating mode to another. This control member 34 may be constituted by a button used for setting the time of the watch 10 or by a button used to access the various functions of the watch 10. Thus, as soon as the control member 34 is actuated the microcontroller 26 can control the watch 10 in active mode.

The operation of the watch 10 according to the invention is as follows.

When the watch 10 is worn by a user, for example on the wrist in the case of a wristwatch, it undergoes accelerations of varying intensities due to natural movements made by the user. These accelerations are measured by the accelerometer 30 and transmitted to the microcontroller 26 which deduces that the watch 10 is worn. The watch 10 is then kept in its active mode and the hands 20, 22 are rotated to display the time.

When the user leaves the watch 10, and the pose for example on a table, the watch 10 is stationary so that no acceleration can be measured by the accelerometer 30. The microcontroller 26 deduces while the watch 10 n is more worn and it triggers the transition to standby mode so as to minimize the consumption of the watch 10 in electrical energy.

Thus, the autonomy of the watch 10 according to the invention is greater with equal battery capacity 18.

Preferably, the electronic circuit 14 controls the watch 10 in standby mode when the accelerometer 30 has not measured any acceleration for a determined duration, and / or when the measured acceleration values are below a threshold value, which allows to avoid a switch to untimely standby mode, for example when the wearer of the watch 10 is motionless for a few moments.

In standby mode, the microcontroller 26 cuts off the power supply of the display means 16 with electrical energy, which causes the rotation of the hands to stop. 20, 22. However, the time continues to be counted down to allow the watch 10 to keep in memory the current time.

For this purpose, the electronic circuit 14 comprises means 36 for storing the angular position occupied by the needles 20, 22 at the time of their stop. Thus, when the watch 10 goes back to active mode, the microcontroller 26 is able to control the rotation of the needles 20, 22 from their stop position to their angular position corresponding to the current time.

As soon as the accelerometer 30 measures an acceleration, the microcontroller 26 deduces that the watch 10 is used again so that it triggers the transition to active mode.

Claims (9)

Electronic watch (10) comprising a housing (12) containing an electronic control circuit (14) and display means (16) supplied with electrical energy by an accumulator or a battery (18), the watch (10) comprising a active mode of operation, wherein the electronic circuit (14) controls the display of the current time by the display means (16), and a standby mode of operation, wherein the electronic circuit (14) controls the stopping the display means (16), the electronic circuit (14) triggering the transition from one operating mode to another depending on the signal produced by a sensor (30), characterized in that the sensor (30) consists of an accelerometer (30) which is arranged inside the housing (12) and which has at least one measurement axis of the acceleration experienced by the watch (10), so that the electronic circuit (14) can determine if the watch (10) is worn, in order to switch to ac mode tif. Watch (10) according to the preceding claim, characterized in that the accelerometer (30) has several axes for measuring the acceleration so as to detect any acceleration experienced by the watch (10), including when this acceleration does not have of component along one of the axes. Watch (10) according to any one of the preceding claims, characterized in that the accelerometer (30) is constituted by a microstructure made by micromachining in a plate of crystalline material. Watch (10) according to the preceding claim, of the type in which the electronic control circuit (14) comprises a wafer (25) with integrated circuits, characterized in that the accelerometer (30) is mounted directly on the wafer (25) . Watch (10) according to any one of the preceding claims, characterized in that the electronic circuit (14) controls the watch (10) in standby mode when no acceleration has been measured for a predetermined period. Watch (10) according to any one of the preceding claims, characterized in that it comprises a control member (34) which makes it possible to manually trigger the transition from one mode of operation to another. Watch (10) according to any one of the preceding claims, characterized in that the display means (16) are of the analog type. Watch (10) according to the preceding claim, characterized in that the electronic circuit (14) comprises means (36) for storing the position occupied by the display means (16) analog at the time of their stop. Watch (10) according to any one of claims 1 to 6, characterized in that the display means (16) are of the digital type.

Images