A device for measuring humidity in the internal space of a portable watch case

Abstract

To provide a device for measuring the humidity in an internal volume of a watch case.SOLUTION: A measurement device 10 for measuring the humidity in an internal volume 210 of a case 21 of a watch 20 comprises: a watch 20 comprising a case 21 housing an optical system 22; and a management module 30 external to the case 21. The optical system 22 comprises: 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 the light beam 221 has passed through the multi-pass cell 222. The management module 30 comprises a processing unit 31 configured to communicate with the optical system 22 and to process data transmitted thereby, so as 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 vapor that may be present in the internal volume 210 of the case 21.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a device for measuring parameters used in the field of portable timepieces (e.g., wristwatches, pocket watches), and more particularly to a device for measuring humidity in the internal space of a portable timepiece case.

[0002] In particular, the present invention relates to a device for measuring humidity in the internal space of a portable timepiece case.

Background Art

[0003] Today, all portable timepieces are designed to be waterproof, i.e., to withstand the penetration of water in liquid form into the internal space of the case. This means that, depending on the degree of watertightness, the portable timepiece can be used in a humid environment or immersed in water. For example, a diving watch is designed to withstand the pressure generated by water on the walls of its case up to a depth of at least 100 m.

[0004] To ensure waterproofness, joints are attached to specific case components such as gaskets, bezels, the back of the portable timepiece, crowns, and push buttons at their assembly interfaces.

[0005] However, the mechanical properties of the joints change over time and according to the climatic conditions in the environment where the portable timepiece is used, which may result in a decrease in waterproofness. In such a case, the portable timepiece may allow water to penetrate, causing condensation to occur on the surface of the internal space and components, and may lead to oxidation of metal components and deterioration of polymer components.

[0006] In addition, joints and / or certain outer parts made of polymer materials may be permeated. That is, it may allow a specific amount of water vapor present in the environment where the portable watch is located to pass through, so that the inside and outside of the portable watch may reach an equilibrium state. This equilibrium may be achieved in a few hours or a few weeks, depending on the structure of the portable watch, the quality of the joints, and the environment. In this case, the amount of vapor present in the portable watch may vary depending on the wearer and the difference in outside air temperature over time.

[0007] To suppress the risk of a significant increase in the water permeability or a significant decrease in the waterproofness of the polymer material used, it is recommended to perform regular maintenance work on the portable watch, and it is necessary to open the portable watch during this maintenance work. Opening the portable watch requires a watch technician and is relatively costly because all joints need to be systematically replaced.

[0008] Therefore, a humidity measurement device has been developed and incorporated into the portable watch case to measure humidity and detect abnormalities related to the presence of water or water vapor without opening the case.

[0009] For example, there is a measurement device in the form of a small electronic module that can measure and record the values of various environmental parameters including relative humidity. Such an electronic module can measure the humidity inside the portable watch case via a dedicated sensor. Then, the measured relative humidity value can be wirelessly sent to the docking station of the portable watch.

[0010] However, one of the problems with such measurement devices is that they require a power source such as a battery. Therefore, these devices are not at all suitable for mechanical portable watches or portable watches with a small size. Also, in the case of electronic portable watches, these devices may limit autonomy or require the use of a large-capacity battery or rechargeable battery, which may not be compatible with the volume of the space inside the portable watch case.

[0011] Note that the concept of waterproofness in this document should be noted to generally mean resistance to water, regardless of whether it is in the form of liquid or vapor.

[0012] The term "humidity" means the relative humidity of the air.

Summary of the Invention

Means for Solving the Problems

[0013] In such a situation, the present invention solves the above problems by providing a measurement device for measuring the humidity in the internal space of a portable watch case. This measurement device includes a portable watch having a case that houses an optical system, and a management module that is outside the case. The optical system includes a light beam transmitter, a multipass cell intended for the light beam to pass through, and a light beam receiver that receives the light beam after it passes through the multipass cell. The management module includes a processing unit configured to communicate with the optical system and process the data transmitted thereby, and thereby determine the humidity present in the internal space of the case based on the absorption of the light beam by water vapor that may be present in the internal space of the case.

[0014] In certain embodiments, the present invention can further include one or more of the following features, either alone or in any technically possible combination by combining them.

[0015] In certain embodiments, the processing unit is configured to control the transmitter to send or stop sending the light beam.

[0016] In certain embodiments, the transmitter is a vertical cavity surface emitting laser or an external cavity surface emitting laser.

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

[0018] In certain embodiments, the power source is incorporated into the internal space of the portable clock.

[0019] Other features and advantages of the present invention will become apparent by reading the following detailed description given as an exemplary embodiment with reference to FIGS. 1 and 2. Note that the present invention is not limited to these embodiments.

Brief Description of the Drawings

[0020]

Figure 1

Figure 2

Modes for Carrying Out the Invention

[0021] FIGS. 1 and 2 schematically show a device 10 for measuring the humidity in the internal space 210 of a portable clock case by cavity ring-down spectroscopy. The internal space of the case is defined by the bezel, the back part and the middle part by a well-known method and houses the timepiece movement.

[0022] The measuring device 10 according to the present invention includes a portable clock 20, an optical system 22 housed in the case 21 of the portable clock 20, and a management module 30 outside the case 21. The management module 30 is considered to be "outside" the case 21 in the sense that it is not housed in the internal space 210 of the case 21.

[0023] The management module 30 includes a processing unit 31, and this processing unit 31 is configured to communicate with the optical system 22 and process the data transmitted thereby. The optical system 22 and the management module 30 can preferably communicate by wireless means.

[0024] Advantageously, the management module 30 may further comprise a display member 32 configured to display the representation of the processed data, as will be described in more detail below.

[0025] The optical system 22 is fixed, for example, in the middle part, on the dial of the portable timepiece 20, or on the structure of the timepiece movement such as a plate or a bridge. As can be seen from the schematic diagrams of FIGS. 1 and 2, the optical system 22 includes a transmitter 220 that sends a light beam 221, a multipass cell (MPC) intended to allow the light beam 221 to pass through, and a receiver 223 intended to receive the light beam 221 after the light beam 221 has passed through the multipass cell 222.

[0026] Note that such an optical system 22 is configured such that the light beam 221 moves between the transmitter 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 other than the medium of the internal space 210 of the case 21.

[0027] When the light beam 221 propagates in the medium of the internal space 210 of the portable timepiece 20, which is air in this case, the light beam 221 interacts with the medium, thereby changing the properties of the light beam 221.

[0028] In particular, in the present invention, this device aims to measure the humidity present in the internal space 210 of the case 21 of the portable timepiece 20 by evaluating the change in the absorption of the light beam 221 by water vapor that may be present in the internal space 210 of the case 21. Since the absorbance is measured and the absorption coefficient of water molecules, especially water vapor, is known, the concentration of water present in the air of the internal space 210 can be estimated.

[0029] The transmitter 220 comprises a collimated light source capable of sending the light beam 221 through the multipass cell 222 to the receiver 223. For example, the transmitter 220 is an external cavity surface emitting laser, which is also referred to as an external cavity diode laser (ECDL) or a vertical cavity surface emitting laser (VCSEL).

[0030] Advantageously, the transmitter 220 is configured to send a light beam 221 having a wavelength corresponding to one of the wavelengths absorbed by water vapor, in particular a wavelength of 968.3 nm, 1388 nm, 2741.41 nm, 2662.48 nm or 6270.77 nm.

[0031] Also, the transmitter 220 is configured to communicate with the processing unit 31. In particular, the processing unit 31 is configured to send commands to the transmitter 220 to send the light beam 221 or to stop sending the light beam 221.

[0032] The multipass cell 222 comprises at least two reflecting elements 224 that are reflective at the wavelength of the light beam 221, as schematically shown in FIGS. 1 and 2, which are made of, for example, aluminum oxide or titanium dioxide. Thanks to the configuration of the transmitter 220 and / or the reflecting elements 224, the light beam 221 is reflected multiple times by both reflecting elements 224. Thus, the optical path of the light beam 221 becomes considerably longer, which makes it possible to increase the absorption of the light beam 221 by water vapor that may be present in the space and improve the sensitivity of the measurement. In particular, the longer the optical path length, the more accurate the humidity measurement by the measuring device 10. As an example, the multipass cell 222 can be configured such that the optical path is from several cm, for example 10 cm, to several m, for example 10 m.

[0033] Receiver 223 includes an optical light sensor with a photodiode. Further, this receiver 223 further includes an analog / digital converter for converting an analog value related to the intensity of the light beam 221 into data that can be used by a processing unit 31 such as a digital value. Note that the receiver 223 can include a plurality of optical sensors, which makes it possible to amplify the difference between signals from these optical sensors to reduce the influence of relative intensity noise of the light beam 221 or to optimize the dynamic range of the analog / digital converter. Also, it is possible to arrange an optical bandpass filter in front of the receiver 223 so as to receive only the wavelength sent by the transmitter 220.

[0034] Receiver 223 is configured to communicate with the processing unit 31 and send data representing the intensity of the light beam 221 sent by the transmitter 220 to this processing unit 31.

[0035] The processing unit 31 can be an integrated circuit including hardware and software resources, particularly at least one processor associated with a memory element. This processing unit 31 can execute instructions for implementing a computer program in order to contribute to determining the measured value of the humidity in the internal space 210 of the case 21 of the portable clock 20.

[0036] In particular, the processing unit 31 can control the transmitter 220 as described above and is configured to evaluate the absorption of the light beam 221 by water vapor that may be present in the internal space 210 of the case 21. In particular, the processing unit 31 can perform signal processing operations using signal modulation operations and synchronous detection operations. The processing unit 31 has, for example, in its storage element, one or more look-up tables between the intensity value of the light beam 221 and / or the absorption coefficient of the light beam 221 by water vapor, which include humidity values associated with the intensity value of the light beam 221 and / or absorption coefficients, thereby determining the humidity in the internal space 210 of the case 21.

[0037] As shown in FIG. 1, the management module 30 can include a power source 33 configured to supply power to an optical system, particularly a transmitter 220 and a receiver 223, using, for example, a wired or wireless power supply element. By way of example, the wired power supply element can be respectively constituted by a connector or a plug intended to be respectively connected to a plug or a connector disposed in the case 21 of the portable clock 20. Also, the wireless power supply element can include an electromagnetic induction element.

[0038] The display device 32 can be analog or digital. In particular, this display device 32 can advantageously display a plurality of distinct visual signals representing the humidity value determined by the processing unit 31. By way of example, this display device 32 can be constituted by, for example, a display screen, a light-emitting scale, or a needle configured to move in a value scale arranged in an arc shape.

[0039] Note that typically, the embodiments and implementation examples considered above are described by way of example, and thus, other alternative embodiments and implementation examples can also be considered.

[0040] In particular, as shown in FIG. 2, the power source 33 can be mounted not within the management module 30 but within the internal space 210 of the portable clock 20. In this case, such a power source 33 can be formed by a relatively small-sized battery or rechargeable battery. This exemplary embodiment of the present invention is preferably applicable to an electronic portable clock. This is because the battery or rechargeable battery constituting the power source 33 can be a battery or rechargeable battery that supplies power to the timepiece movement.

[0041] In addition, the management module 30 can be configured to communicate information representing data processed by the processing unit 31 with an electronic device such as a smartphone or a tablet that can display the representation of the processed data.

Explanation of Signs

[0042] 10 Measuring device 20 Portable clock 21 Case 22 Optical system 30 Management module 31 Processing unit 32 Display member 33 Power source 210 Internal space 220 Transmitter 221 Light beam 222 Multipass cell 223 Receiver 224 Reflective element

Claims

**Claim 1** A measurement device (10) for measuring the humidity in the internal space (210) of the case (21) of a portable clock (20), comprising a portable clock (20) having a case (21) that houses an optical system (22), and a management module (30) located outside the case (21), wherein the optical system (22) includes a transmitter (220) that sends a light beam (221), a multipass cell (222) intended for the light beam (221) to pass through, and a receiver (223) intended to receive the light beam (221) after it has passed through the multipass cell (222), the management module (30) includes a processing unit (31) configured to communicate with the optical system (22) and process the data transmitted thereby, thereby determining the humidity in the internal space (210) of the case (21) based on the absorption of the light beam (221) by water vapor that may be present in the internal space (210) of the case (21). A measurement device (10) characterized by the above. **Claim 2** The measurement device (10) according to claim 1, wherein the processing unit (31) is configured to control the transmitter (220) to send or stop sending the light beam (221). **Claim 3** The measurement device (10) according to claim 1, wherein the transmitter (220) is a vertical cavity surface emitting laser or an external cavity surface emitting laser. **Claim 4** The measurement device (10) according to claim 1, wherein the management module (30) includes a power source (33) configured to supply power to the transmitter (220) and the receiver (223). **Claim 5** The measurement device (10) according to claim 4, wherein the power source (33) is incorporated into the internal space (210) of the portable clock (20). ​

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