JPS59159084A - Pressure detecting section construction for electronic time piece with water depth-meter - Google Patents

Abstract

PURPOSE:To always enable a stable and highly accurate measurement of pressure by filling at least a part of pressure introduction holes outward from a silicone diaphragm type pressure sensor with a rubber-like elastic material to protect the diaphragm from chemical and physical influences. CONSTITUTION:A small hole in a windproof glass 5 is provided to introduce pressure outside a timepiece into a diaphragm of a sensor 8 and filled with a rubber- like elastic material 13 upto an external opening. As the timepiece is put into water, a difference between pressures inside and outside a case is applied to the rubber-like material 13 of the pressure introduction hole through a mesh- like small holes of a cover plate 6 and further transmitted to the diaphragm of the sensor 8 without damping to generate an electrical signal according to the water depth. With such an arrangement, there is no infiltration of seawater, sweat and air into the pressure introduction hole, which keeps the sensor 8 from directly contacting these materials thereby ensuring accurate transmission of pressure. Thus, a pressure detection mechanism with an improved weathering property can be obtained.

Description

[Detailed Description of the Invention] This invention relates to an electronic watch with a built-in pressure gauge. This relates to the structure of the part that detects the pressure difference between the inside and outside of the exterior case of Time 1.

An object of the present invention is to provide an electronic watch with a built-in pressure measuring device so that a diver can know both the time and the depth of diving underwater. In the depth-gaining diver Wosochi,
The purpose of the present invention is to improve the durability of a pressure measuring device and enable highly accurate and highly stable depth measurement.

recent years. Scuba diving technology has made great strides.
Along with this, he took up diving as a profession. The number of people who enjoy diving as a leisure activity is rapidly increasing. These divers were looking for a watch that they could use with confidence while diving. In recent years, diver watches with an exterior structure that can withstand water pressure of several hundred atmospheres have become commercially available, and these diver watches have become a must-have item for divers to prevent diving accidents due to damage to the watch. .

on the other hand. In order to ensure diving safety, diving depth is one of the most important requirements, along with diving time. During a dive, a diver must constantly check the diving depth, calculate the related air consumption, and adjust the ascent speed. Of course. Diving too deep is dangerous in itself and must be avoided.

Diving depth has such an important meaning.

Currently, the only measuring instruments available on the market are large ones that restrict the movement of the diaper underwater, ones that have problems with accuracy and stability, or ones that are very expensive. do not have. For this reason, many dialers rely on visual measurements and experience, which is a very dangerous situation.

A measuring device that measures the depth of a dive is defined as a depth meter, and the first method of measuring depth is to measure the water pressure applied to the depth meter and divide it by the density of the water to find the depth. Although this method requires some correction due to the difference in the density of freshwater and seawater, it is ideal as a depth gauge for dipers because it measures the physical force that directly affects the dipers.

There is an opinion that a water pressure gauge that directly displays the pressure is more useful because the physical element that directly affects the diper is pressure itself. Considering that there is, the depth gauge referred to here includes a water pressure gauge, but σ)0 The exterior of the Diaper Watch is a very robust sealed container, and there is almost no change in the internal volume at a depth of about 100 meters.
Therefore, the internal pressure is kept approximately equal to atmospheric pressure. If a small hole is provided in a part of such an exterior, and the small hole is sealed by a diaphragm and the diaphragm is submerged in water, a stress strain proportional to the water pressure is generated in the diaphragm. The stress strain can be converted into an electric signal by a strain gauge, amplified, and displayed as water depth by an indicator, and the pressure measuring device used in the present invention is also realized by applying this principle. Ru.

The structure of the pressure detection section according to the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of a silicon diaphragm type pressure sensor for detecting water pressure used in the present invention.

Figure 2 is its plan view.

The silicon diaphragm type pressure sensor consists of a silicon single crystal plate 1 with a side of several millimeters square and a thickness of several hundred microns, and a semiconductor resistor 6 is diffused and formed on the surface of a diaphragm 2 formed by carving one side of the plate into a circular shape. It is something.

On the left and right surfaces of the diaphragm 2 in FIG.

When a pressure difference occurs, distortion occurs in the diaphragm 2, and as a result, the resistance value of the semiconductor resistor B changes.

As shown in FIG. 2, the semiconductor resistors 3 are formed at four locations on the periphery of the diaphragm 2 in aligned directions, and their resistance values are approximately equal.

The four semiconductor resistors 6 are bridge-connected as shown in the circuit diagram shown in FIG.
ut is obtained.

Vout=-eE (Here, R is the resistance value of each semiconductor resistor 6 when there is no pressure difference ΔP, and ΔR is the change in resistance value that occurs in each semiconductor resistor B in response to the pressure difference ΔP.

E is the voltage of the power supply applied to the bridge.

Since the semiconductor resistor 6 exhibits a piezoresistance effect against strain,
The change in resistance ΔR that occurs in response to the pressure difference ΔP is extremely large, and has a sensitivity several hundred times that of a normal metal foil strain gauge. In addition, the silicon thin plate diaphragm has a large elastic limit, and has many excellent characteristics such as residual strain ``-/'', material fatigue, and aging force ''=/J. To have and see.

Silicon diaphragm pressure sensor (currently the most useful pressure sensor and is in practical use for various pressure measurements.

The thin silicon plate H-Fram type pressure sensor, which has these excellent features, seals a small hole made in a part of the exterior of the dyno cube and detects the pressure difference on both sides. In this case, one side of the diaphragm will be in direct contact with the outside world.

Due to its nature, Diaper watches are immersed in liquids, come into contact with corrosive substances produced by the decomposition of sweat, and are exposed to ozone lynch air, so it is difficult to avoid the chemical effects of these substances. Care must be taken to ensure that no influence is applied to the silicon diaphragm type pressure sensor.

In addition, the seawater and sweat that entered the small holes provided in the exterior evaporation will prevent crystals of monozeta-salt from precipitating in the small holes, and the small holes themselves will not become clogged due to the accumulation of dirt. must be done.

The present invention proposes a structure of a pressure detection section that protects the diaphragm of the sensor from such chemical and physical influences and allows stable and accurate pressure measurement at all times.

FIG. 4 is an external plan view showing an embodiment of the device having a depth meter function using the silicone diaphragm pressure sensor described above.

This embodiment is a digital display wristwatch using an electro-optical display element. (1) Display surface 4 shows the time 10:09:35 a.m., the elapsed time from the start of the dive 0 hours 45 minutes, and the water depth. 24. , 6 m are displayed. A pressure detection section is provided in a part of the windshield 5 that covers the display surface of the watch, and a cover plate 6 mechanically protects the pressure detection section.
It is fixed to the surface of the windshield 5.

5, 6, 7, and 8 are cross-sectional views of the pressure detection section that can be used for the electronic time opening shown in FIG. This is an example.

In the four embodiments, the -1- side of the drawings represents the outer surface of the timepiece exterior, and the lower side represents the inner surface of the timepiece exterior.

Referring to FIG. 5, a cover plate 6 having a mesh-like small hole is fixed to the outer surface of the windshield 5. As shown in FIG.

Also, a partially opaque paint 7 is applied to the inner surface of the windshield 5.
is applied, and the digital display is separated. A small through hole is provided in the windshield 5 in the lower part of the cover plate 6, and the silicone diamondorum type pressure sensor 8 (hereinafter referred to as sensor) is hermetically fixed to the opening inside the windshield 5. .

The four terminals of the resistance bridge of the sensor 8 are connected to the four pattern wirings 10a of the terminal board 10 by ultra-fine conductive wires 9, and further connected to the signal processing circuit (
(not shown).

A diaphragm protective cover 12 is fixed on the pattern wiring surface of the terminal board 10 to protect the wiring of the seventh pin ±-8 and the thin conductor wire 9. The diaphragm protective cover 12, which protects it from damage, has a small hole so as not to limit the size of the back pressure chamber of the sensor 8.

The small hole provided in the windshield 5 is a pressure introduction hole for introducing external pressure of the watch into the diaphragm of the sensor 8. A very small solid material, ie, a rubber-like elastic material 16, is filled up to the outer opening of the windshield 5.

The rubber-like elastic material 16 has a very small Young's modulus, and is confined to a region with a large bone-to-boanson ratio and small deformation, so it is difficult to maintain the elasticity of the insula introduction hole.
The pressure applied to the H110 section reaches the deepest part of the pressure introduction hole.
] is transmitted to the diaphragm of the sensor 8 with almost no deterioration.

When a diver equipped with a water pressure detection section having such a structure is placed in water, the pressure difference between the inside and outside of the special training exterior is applied to the rubber-like elastic material 13 of the FE force introduction hole through the small mesh holes of the cover plate 6. '' is further transmitted to the diaphragm of sensor 8).

As a result, the diaphragm of the sensor 8 is deformed inward at the time 111, and this distortion causes an imbalance in the Brinnon resistance, generating an electrical signal depending on the water depth.

If the pressure introduction hole is filled with the rubber protrusion + 1 material IP1is in this way, seawater, sweat, and air will not enter the pressure introduction hole, so that the sensor 8 will be directly exposed to the air.11. Since these substances (C) do not come into contact with each other and pressure is transmitted correctly, an excellent pressure detection mechanism with extremely good weather resistance is realized.

In the embodiment shown in FIG. 6, the sensor 8 is connected to the windshield 5
(-1: The sensor mount 14 is fixed directly to the sensor mount 14, and the structure is such that the sensor mount 14 is fixed to the windshield 5a.

There is a small hole passing through the center axis of the sensor mount 14, and the sensor 8 is hermetically fixed to the opening inside the sensor mount 14. A screw is provided on the outer periphery of the sensor mount 14, and is engaged with a cover plate 6a having an internal thread, thereby attaching the sensor mount 14 to the windshield 5a. It is fixed at In this fixing, a waterproof gasket 15 is compressed and fixed between the sensor mounting base 14 and the parting paint 7 on the lower surface of the windshield 5, and has a waterproof function.

The terminal wiring and protective structure of the sensor 8 are the same as those in the embodiment shown in FIG. 5, so their explanation will be omitted. The small hole of the sensor receiving stand 14 is a pressure introduction hole, and the rubber-like elastic material 16 is similar to the embodiment of FIG. 5 except that the windshield 5 in the embodiment of FIG. Filled.

FIG. 7 shows an embodiment in which the sensor mounting base 14a is inserted from the outside surface of the windshield 51). Sensor mounting base 14
a is press-fitted and fixed to the windshield 51) via a waterproof gasket 15a.

The central axis of the sensor mount 14a has a small penetrating hole whose diameter increases from the inside to the outside, and the sensor 8 is hermetically fixed to the opening inside the sensor mount 14a, and is made of a rubber-like elastic material. 16 is filled in the carved part and part of the small hole of the sensor 8.

A sensor mounting base 14 is installed on the outside of the sensor mounting base 14a.
Cover plate 6b having a small hole that passes through the small hole of a
is fixed. The terminal wiring and protective structure of the sensor 8 are the same as those in the embodiments shown in FIGS. 5 and 6, so their explanation will be omitted.

In this example, only a part of the small hole is filled with the rubber-like elastic material 13, but this is because the shape of the small hole is different from the example shown in FIGS. 5 and 6. This is because problems such as clogging of the small holes themselves due to dirt and contamination do not occur.

In the embodiments shown in FIGS. 5, 6, and 7 described above, the sensor is placed in the inner opening of the pressure introduction hole, but in the embodiment shown in FIG. 8, the sensor is located in the pressure introduction hole. This figure shows the case where it is placed in the outer opening.

In this embodiment, the sensor 8 is fixed to the sensor mount 14b so as to seal the small hole provided in the central axis of the sensor mount 14b from the outer surface. It is electrically connected to a fourth conductive bottle 16 which passes through b and is hermetically fixed by a very thin conductive wire 9.

The area around the wiring part of the sensor 8 and the ultra-fine conductive wire 9 is filled with a rubber-like elastic substance 16 to protect it physically and chemically. protected.

Further, the rubber-like elastic material 16 includes a light-shielding frame material to provide optical protection. The sensor mounting base 14b is inserted from the outside of the exterior and press-fitted into the windshield 5c via a waterproof gasket 15b, and the sensor 8 is mounted via a conductive bottle 16 and a spring 11 (not shown) that is press-fitted to one end thereof. It is electrically coupled to the signal processing circuit.

The case where the water pressure detection part is provided on the windshield surface of the watch has been described above with reference to four different embodiments. Instead, it may be replaced with the back cover of the watch exterior or the exterior body (case body).

In this case, space constraints tend to occur in the mounting area, but
On the other hand, it has the advantage that the display surface of the watch can be expanded, so it can be applied to analog display wristwatches with pointer displays.

FIG. 9 is an external plan view showing an embodiment of an analog display wrist watch equipped with a depth meter, in which a pointer-type depth display section 18 is also provided in a part of the pointer-type time display surface 17.

In this embodiment, the water pressure detection section is shown in Figure 2, cover plate 6.
As can be understood from the position of
It points from the 0 o'clock position parallel to the page toward the center of the clock.

Next, the above rubber-like elastic material will be explained.

In the present invention, the diaphragm of a silicon diaphragm type pressure sensor, the fixed part between the sensor and the base of the sensor, the pressure introduction hole, the wiring drawn out from the sensor, etc. are physically and chemically protected. The following three items are particularly important as characteristics necessary for a rubber-like elastic material used for the purpose of not impairing the detection ability of the detection section.

First, the material must be as flexible as possible and not attenuate the pressure transmitted to the diaphragm. To achieve this, the material must have a Young's modulus as small as possible, a Poisson's ratio as large as possible, and the properties of which are not affected by temperature or pressure.

However, the area of the diaphragm of a silicon diaphragm pressure sensor is small, a few square millimeters, and its mechanical displacement is small, so even though it is called a rubber-like elastic material, its elastic limit range does not necessarily have to be large. It can also be a property.

Second, it must be a material that does not undergo deterioration even when constantly exposed to seawater, sweat, ozone, etc. This characteristic is necessary not only for strength reasons, but also for keeping the sensitivity of the depth meter stable for a long period of time.

Thirdly, it must have good filling properties. The pressure introduction hole provided on the exterior of the Diaper Watch has a small diameter and is relatively deep, but it must be filled to every nook and cranny without any gaps, and it is necessary to wrap the extremely fragile ultra-fine conductor wiring. .

Therefore, it is desirable to use a substance that is in a liquid state with high fluidity during filling and loses its fluidity after filling is completed.

Silicone rubber is a material that has the above-mentioned important properties, and is most suitable as the rubber-like elastic material of the present invention. Silicone rubber is manufactured with various characteristics to suit various application fields.

A two-component RTV type curing at room temperature is suitable for the application of the present invention. Such silicone rubber has the original properties of silicone rubber, such as very soft hardness and excellent heat resistance, cold resistance, and weather resistance after curing.

Above is 4? About electronic watches with depth gauges that use silicon diaphragm type pressure sensors. We gave a detailed explanation focusing on the structure of the water pressure detection section.

According to the present invention, it is not only possible to detect water pressure by incorporating a silicon diaphragm type pressure sensor into a diper watch used under extremely harsh environmental conditions, but also to enable accurate operation over a long period of time. Now you can. Additionally, the water pressure detection unit has been made smaller and the design has greater flexibility, making it possible to incorporate a depth gauge without compromising the design of the watch.

[Brief explanation of the drawing]

1 and 2 are a sectional view and a plan view showing the structure of a silicon diaphragm type pressure sensor used in the electronic timepiece with depth gauge of the present invention, and FIG. It is a principle circuit diagram explaining the connection of the resistance bridge of the diaphragm type pressure sensor, and FIGS.
Each of the figures is a plan view of the external appearance of a depth gauge electronic timepiece according to each embodiment of the present invention, and FIGS. FIG. 3 is a cross-sectional view showing the structure of a pressure detection section according to an embodiment. 5.5a%5b, 5c...Windshield glass. 6.6a, 6b, 6cm---h bar plate, 7...
·paint. 8...Silicon diaphragm type pressure sensor. 9...Extremely thin conductor wire. 10...Terminal board. 11...Pressure spring, 12...Diaphragm protection cover. 14.14a, 14b --= Sensor mounting base. 15.15a, 15b --- Waterproof packing. 16... Conductive pin. 16... Rubber-like elastic substance. Figure 1 Figure 2 Figure 3 @ Figure 4 δ Figure 9 8 484- Figure 8

Claims (1)

[Claims] (1) A pressure introduction hole for introducing external pressure is provided in a part of the exterior,
In an electronic timepiece with a depth gauge having a pressure detection part in which the pressure introduction hole is sealed with a silicon diaphragm pressure sensor, at least a portion of the pressure introduction hole outside the silicon diaphragm pressure sensor is filled with a rubber-like elastic material. Features: Pressure detection structure of electronic watch with depth gauge. (2. The rubber-like elastic material described in claim 1 is
A structure of a pressure detection part of an electronic watch with a depth gauge characterized by being made of silicone rubber.