DEVICE FOR MEASURING THE HUMIDITY LEVEL IN THE INNER VOLUME OF A WRISTWATCH CASE

Description

Technical field of the invention

[0001] The invention relates to parameter measurement devices applied to the field of watchmaking and in particular to devices for measuring the degree of humidity in the internal volume of a watch case.

[0002] More specifically, the invention relates to a device for measuring the degree of humidity in the internal volume of a watch case. Technological background

[0003] Nowadays, all watches are designed to be water-resistant, meaning they can withstand the penetration of liquid water into the internal volume of their case. This property allows a watch, depending on its level of water resistance, to be used in humid environments or even submerged. For example, dive watches are designed to withstand the pressure generated by water on the case walls, at a minimum depth of 100 meters.

[0004] To guarantee their water resistance, the watches are equipped with sealing gaskets positioned in the assembly interfaces of certain components of their case, such as the crystal, the bezel, the case back, the crown and the push buttons.

[0005] However, the mechanical properties of the seals change over time and according to the climatic conditions of the environment in which the watches are used, which can lead to a deterioration of their water resistance. The watches may then become permeable to water, and condensation may appear within their internal volume and on the surface of their components, which can cause oxidation of the metallic components or degradation of the polymer components.

[0006] Furthermore, the seals and / or certain casing components made of polymer materials can be subject to permetamination, meaning they allow a certain amount of water vapor from the surrounding environment to pass through in order to maintain equilibrium between the inside and outside of the watch. This equilibrium can be reached in a few hours or a few weeks, depending on the quality of the watch's construction and the seals, as well as the environment. In this case, the amount of water vapor present inside the watch may vary depending on how often it is worn and on changes in external temperature over time.

[0007] To limit the risk of loss of water resistance or excessive permeation of the polymer materials used, it is recommended to have your watch serviced regularly, which requires opening it. This service is relatively expensive as it involves a watchmaker and the systematic replacement of all the gaskets.

[0008] Humidity measurement devices have therefore been developed and integrated inside watch cases in order to measure the degree of humidity and detect an anomaly related to the significant presence of water or water vapor without having to open them.

[0009] For example, there are measuring devices in the form of a small electronic module capable of measuring and recording values ​​for various environmental parameters, including relative humidity. Such an electronic module can measure the humidity level inside the watch case via a dedicated sensor. The measured relative humidity values ​​can then be wirelessly transmitted to a watch docking station.

[0010] However, a drawback of these measuring devices is that they require a power source, such as a battery. Therefore, these devices are poorly suited to mechanical watches or small watches. Furthermore, for electronic watches, these devices can negatively impact battery life or necessitate the use of a larger capacity battery, which may not be compatible with the available space inside watch cases. EP 3 985 455 A1 discloses a device for measuring the degree of humidity within the internal volume of a watch case by means of the absorption of a light beam, where the optical emitter and sensor are located outside the watch.

[0011] It should be noted that the concept of sealing in this text refers generally to sealing against water, in liquid or vapor form.

[0012] Furthermore, the term "humidity level" refers to the relative humidity of the air. Summary of the invention

[0013] The invention resolves the aforementioned drawbacks by proposing, for this purpose, a device for measuring the degree of humidity in the internal volume of a watch case comprising: a watch comprising a case in which is housed an optical system, said optical system comprising a light beam emitter, a multi-reflective cell through which the light beam is intended to pass, and a light beam receiver intended to receive said beam once it has passed through the multi-reflective cell; an external management module to said case, comprising a processing unit configured to communicate with the optical system and to process data transmitted by the latter in order to determine the degree of humidity present in the internal volume of the case from the absorption of the light beam by the water vapor likely to be present in said internal volume of the case.

[0014] In particular embodiments, the invention may further include one or more of the following features.

[0015] In particular embodiments, the processing unit is configured to control the emitter so that it emits or stops the emission of a light beam.

[0016] In particular embodiments, the emitter consists of a vertical cavity laser emitting from the surface or a vertical external cavity laser emitting from the surface.

[0017] In particular embodiments, the management module includes a power supply configured to supply power to the transmitter and receiver.

[0018] In particular embodiments, the power source is integrated into the internal volume of the watch. Brief description of the figures

[0019] Other features and advantages of the invention will become apparent upon reading the following detailed description, given by way of non-limiting example, with reference to figures 1 and 2which schematically represent a device for measuring the degree of humidity in the internal volume of a watch case according to the present invention, in examples of embodiments. Detailed description of the invention

[0020] THE figures 1 and 2 schematically represent a device 10 for measuring the degree of humidity in the internal volume (210) of a watch case by optical cavity absorption spectroscopy. The internal volume of the case is defined, in a way known per se, by a crystal, a back and a case middle, and houses a watch movement.

[0021] The measuring device 10 according to the present invention comprises a watch 20, an optical system 22 housed in the case 21 of said watch 20, and a management module 30 external to said case 21. The management module 30 is said to be "external" to the case 21 in the sense that it is not housed in the internal volume 210 of the latter.

[0022] The management module 30 includes a processing unit 31 configured to communicate with the optical system 22 and process data transmitted by the latter. The optical system 22 and the management module 30 are capable of communicating primarily wirelessly.

[0023] Advantageously, the management module 30 can also include display devices 32 configured to display a representation of the processed data, as described in more detail later in the text.

[0024] The optical system 22 is fixed, for example, to the case, to a watch dial 20, or to a structure of the watch movement such as a mainplate or a bridge. As can be seen in the schematic representation of the figures 1 and 2 , the optical system 22 comprises a light beam emitter 220 221, a multiple reflection cell, also called multi-pass cell Or PCin English, that the light beam 221 is intended to pass through, and a receiver 223 of the light beam 221 intended to receive said beam once it has passed through the multiple reflecting cell 222.

[0025] It should be noted that such an optical system 22 is configured so that the light beam 221 travels between the emitter 220 and the receiver 223 without being guided by an optical guide, such as an optical fiber or a dielectric waveguide, i.e. without being confined in a medium different from that of the internal volume 210 of said box 21.

[0026] During its propagation in the medium of the internal volume 210 of the watch 20, in this case air, the light beam 221 interacts with said medium, which causes a modification of the properties of said beam.

[0027] In particular, in the present invention, the device aims to measure the degree of humidity present in the internal volume 210 of the case 21 of the watch 20 by evaluating a change in the absorption of the light beam 221 by the water vapor likely to be present in the internal volume 210 of the case 21. It is noted that the absorbance is measured and, knowing the absorption coefficient of the water molecule, in particular of water vapor, the concentration of water present in the air of the internal volume 210 can be deduced.

[0028] The emitter 220 includes a collimated light source capable of emitting a light beam 221 through the multiple reflection cell 222 to the receiver 223. By way of example, the emitter 220 is a surface-emitting external cavity laser, also known as External cavity diode lasers Or ECDLin English, or by a vertical cavity laser emitting from the surface, also known as Vertical-cavity surface-emitting laser Or VCSEL.

[0029] Advantageously, the emitter 220 is configured to emit a light beam 221 whose wavelength corresponds to one of the wavelengths absorbed by water vapor, in particular to a wavelength equal to 968.3 nm, 1388 nm, 2741.41 nm, 2662.48 nm or 6270.77 nm.

[0030] Furthermore, transmitter 220 is configured to communicate with processing unit 31. In particular, processing unit 31 is configured to transmit instructions to transmitter 220 to emit light beam 221 or stop its emission.

[0031] The multiple reflection cell 222 comprises, as schematically shown in the figures 1 and 2at least two reflective elements 224, for example made of aluminum oxide or titanium dioxide, exhibiting reflectivity at the wavelength of the light beam 221. Thanks to the arrangement of the emitter 220 and / or the reflective elements 224, the light beam 221 is reflected several times by each of the reflective elements 224. Thus, the optical path length of the light beam 221 is considerably increased, which enhances the absorption of said light beam 221 by any water vapor that may be present in the volume, thereby improving the sensitivity of the measurement. Indeed, the measurement of the degree of humidity performed by the measuring device 10 is all the more precise as the optical path length increases.As an example, the 222 multi-reflective cell can be configured so that the optical path length is between a few centimeters, for example ten centimeters, and a few meters, for example ten meters.

[0032] The receiver 223 includes an optical light sensor with a photodiode. This receiver 223 is also equipped with an analog-to-digital converter that converts an analog quantity related to the intensity of the light beam 221 into data usable by the processing unit 31, such as a digital value. It should be noted that the receiver 223 can include several optical sensors, which allows the difference in signals from these optical sensors to be amplified in order to reduce the effect of relative intensity noise from the light beam 221, or to optimize the dynamic range of the analog-to-digital converter. It is also possible to place a bandpass optical filter in front of the receiver 223 so that it is sensitive only to the wavelength emitted by the emitter 220.

[0033] The receiver 223 is configured to communicate with the processing unit 31 in order to transmit to it data representative of the intensity of the light beam 221 emitted by the transmitter 220.

[0034] The processing unit 31 can be an integrated circuit comprising hardware and software resources, in particular at least one processor cooperating with memory elements. This processing unit 31 is capable of executing instructions for the implementation of a computer program to contribute to determining the humidity level in the internal volume 210 of the watch case 21 of the watch 20.

[0035] More specifically, the processing unit 31 is capable of controlling the emitter 220 as described previously and is configured to evaluate the absorption of said light beam 221 by water vapor that may be present in said internal volume 210 of the box 21. In particular, the processing unit 31 is capable of performing signal processing operations through signal modulation and synchronous detection. The processing unit 31 includes, for example, in its memory elements one or more lookup tables between values ​​of the intensity of the light beam 221 and / or the absorption coefficients of said light beam 221 by water vapor, with humidity values ​​associated with the intensity values ​​of the light beam 221 and / or the absorption coefficients, in order to determine the humidity level in the internal volume 210 of the box 21.

[0036] As shown by figure 1The control module 30 may include a power supply 33 configured to power the optical system, and in particular the transmitter 220 and the receiver 223, for example, via wired or wireless power elements. For example, wired power elements consist of a connector or a plug, respectively intended to be coupled to a plug or connector arranged on the watch case 21 20. Wireless power elements may include electromagnetic induction elements.

[0037] The display devices 32 can be analog or digital. In particular, they are advantageously suited to display several distinct visual signals representing the value of the degree of humidity determined by the processing unit 31. By way of example, they can consist of a display screen, a luminous scale, a needle adapted to move along a value scale arranged in an arc, etc.

[0038] More generally, it should be noted that the implementation and realization methods considered above have been described as non-limiting examples, and that other variants are therefore conceivable.

[0039] In particular, the power supply 33 can be integrated into the internal volume 210 of the watch 20 and not into the management module 30, as shown in the figure 2Such a power source 33 can then be formed by a relatively small rechargeable battery or cell. This embodiment of the invention is preferably applicable to electronic watches, the rechargeable battery or cell constituting the power source 33 being the same rechargeable battery or cell that powers the watch movement.

[0040] Also, the management module 30 can be adapted to communicate representative information of the data processed by the processing unit 31 to an electronic device, such as a smartphone or an electronic tablet, capable of displaying a representation of the processed data.

Claims

1. Measuring device (10) for measuring the humidity in the internal volume (210) of a case (21) of a watch (20), characterised in that the device includes: - a watch (20) comprising a case (21) housing an optical system (22), said optical system (22) including a transmitter (220) transmitting a light beam (221), a multi-pass cell (222) through which the light beam (221) is intended to pass, and a receiver (223) intended to receive the light beam (221) once it has passed through the multi-pass cell (222); - a management module (30) external to said case (21), including a processing unit (31) configured to communicate with the optical system (22) and to process data transmitted thereby in order to determine the humidity present in the internal volume (210) of the case (21) on the basis of the absorption of the light beam (221) by the water vapour that may be present in said internal volume (210) of the case (21).

2. Measuring device (10) according to claim 1, in which the processing unit (31) is configured to control the transmitter (220) so that it transmits or stops the transmission of a light beam (221).

3. Measuring device (10) according to claim 1 or 2, wherein the transmitter (220) is a vertical-cavity surface-emitting laser or an external-cavity surface-emitting laser.

4. Measuring device (10) according to one of claims 1 to 3, wherein the management module (30) comprises a power source (33) configured to power the transmitter (220) and the receiver (223).

5. Measuring device (10) according to one of claims 1 to 4, wherein the power source (33) is integrated into the internal volume (210) of the watch (20).