Abstract: The invention concerns a method for controlling a continuous rotation miniature motor including a rotor carrying permanent magnets and a stator carrying at least one coil in which an alternating induced voltage is generated when the rotor rotates, this method consisting in maintaining the rotation of said rotor by successive pulses (102) supplied, in respective half periods of the induced voltage (U.sub.i), before the induced voltage reaches a maximum absolute value in each of these half periods. In particular, the time interval (t.sub.1) between a passage through zero of the induced voltage and the beginning of a maintenance pulse (102), provided in the half period following said passage through zero, is constant.

Abstract: A timepiece comprising a generator (1) for generating a supply voltage of a first predetermined value U.sub.1, a barrel with a spring (5, 6), a winding mechanism (5') and a set of hands (7 to 9). The electronic circuit (11, 12) of the timepiece requires a minimum limited supply voltage having a second predetermined value U.sub.2. This circuit comprises a timebase (12) and a regulating circuit (11) for regulating the rotational speed of the generator. According to the invention, a voltage regulator (25) is connected between the generator and said electronic circuit for adjusting its output voltage to said limited second value U.sub.2. The ratio between the absolute value U.sub.1 of the predetermined first value U.sub.1 and the second predetermined value satisfies the relationship U.sub.1 =k.multidot.U.sub.2, k being a factor corresponding at least to the maximum expected variation rate of the absolute value U.sub.1 when the timepiece is worn.

Abstract: A case (2) in which an acoustic transducer (22) is mounted so as to communicate in a watertight manner with the exterior of the case (2) via acoustic energy.The transducer (22) is attached to a membrane (17) separating it in a watertight manner from an inlet cavity (10, 11) which is arranged in the case (2) and is in direct communication with the exterior. The membrane (17) is resiliently applied by its periphery onto a rest surface (12) arranged around the cavity separating the latter in a watertight manner from a deformation chamber (13) situated on the side of the membrane (17) opposite to the inlet cavity while being in communication with the interior of the case. The bottom (13a) of the deformation chamber (13) forms a support surface for said membrane (17) when external static pressure greater than a predetermined value is applied thereto.

Abstract: The batch manufacturing of laminated cells whose spacing is kept constant by means of spacers (11) of diameter d, comprises the steps of forming a first line on a substrate (1), with a hot melt adhesive material for the sealing frames (3) and junction portions (5) between the holes (6) of spacing e and a second line (7) closed at one end (8) to create a filling channel (9), said lines having a constant cross-section So and a height h; depositing the spacers (11) over the substrate (1) and close to the holes (6), destructible or deformable spacers (12) of diameter D such that h>D>d; sealing a second flat deformable substrate (2) with a reduced application of pressure above the holes (6); filling all the cells; exerting a second pressure equal to or greater than the first and heating the zones above the holes to a temperature equal to or greater than that of the hot melt adhesive material; and cutting out each cell.

Abstract: The invention concerns a liquid crystal display device intended, in particular, to form a colour image display screen, of the type including: a first substrate which is transparent on a front side situated on the side of the viewer; and a second substrate arranged on a back side facing the first substrate and extending parallel to the latter. The first substrate is connected to the second substrate in order to delimit between them a cavity in which at least one film of liquid crystal is arranged. The liquid crystal has at least a first state in which it reflects the light of a range of wavelengths of a predetermined colour and at least a second state in which it is transparent. The surface of each substrate facing the other substrate includes electrodes to allow the liquid crystal to pass at least from the first state to the second state or conversely, by selective application of a control voltage to the electrodes.

Abstract: Illumination device for the dial (4) of a display device formed by a case (1) sealed by a crystal (8) arranged above the dial (4) and held by a fitting ring (9), said device including at least one light source (13, 33, 35, 43, 53) arranged in at least one recess arranged in at least one light guide (20, 30, 40, 50) positioned at the periphery of the dial (4), said guide having a polished internal surface (21) oriented towards the dial (4) and an external surface (22) held in a space delimited by the dial (4), the crystal (8) and the inner wall (10) of the fitting ring (9), characterised in that all or part of said external surface (22) of the guide is arranged to allow a progressive increase along the guide (20, 30, 40, 50) of the quantity of light diffused by said external wall gradually as one moves away from one of the light sources (13, 33, 35, 43, 53).

Abstract: In this booster, the voltage across the terminals of the photovoltaic power source (1) is regulated as a function of a reference voltage (V.sub.ref) which is chosen to be substantially equal to the voltage corresponding to the maximum value of the voltage-power curve of this source. The reference voltage generated in the reference generator (9) is compared to the voltage (V.sub.sc) of the source (1), the result is sampled and influences the duty cycle of a control signal (F.sub.c) applied to the switching transistor (7). The latter is responsible for chopping the current flowing from the source to the load (accumulator 6) through an inductor coil (4) and a diode (5).

Abstract: Data transmission system comprising a data transmitter (1) including:swept frame display means (2), anda generator of composite video signals (20, 22) to control the operation of said swept frame display means (2); anda portable information detection device (7) for receiving said transmitted data by said data transmitter (1).The data transmitter (1) further comprises means (23) for modulating at least one of the elementary signals constituting said composite video signals with the data to be transmitted, and said information detection device (7) further comprises any inductive antenna (44, 45) for detecting said modulated elementary signal.

Abstract: A device for charging a battery (11), comprising a photovoltaic cell power source (8) of which the output voltage (USC) is lower than the voltage (VDD) across the terminals of the battery. Said output voltage is raised by a voltage multiplier (26) controlled by a static unit (27) depending on the two respective voltage levels. The source may advantageously comprise a single cell (8). In a timepiece provided with said charging device, the static control unit (27) can also cut off the power supply to display means (13, 23) and time-keeping circuits (21, 22) when the voltage of the battery (11) is too low. The voltage multiplier may use the motor coil (13) of the display means or any other coil used in the timepiece.

Abstract: An oscillator, such as a ring oscillator, uses CMOS transistors. At least some of the transistors have forward biased, current limited source-tub junctions for lowering the threshold voltages of these transistors. This enables the oscillator to operate at very low supply voltages, and it may be used in an electronic timepiece powered by a single photovoltaic cell.

Abstract: A detection device has a transducer (10) for emitting and receiving series of ultrasonic pulses. An integrator (23) integrates echo signals resulting from ultrasonic pulses within a time window so as to produce an integral value. A time-delay circuit (28) is used to control the instant of opening T1 of a time window and a control circuit (25) determines an average value of a number of n integral values and for loading the values of the opening a instant T1 into the time-delay circuit (28) so as to maintain the average value at a steady value. The control circuit (25) determines the average value by loading a first value of T1 in the time-delay circuit before the integration of the first x echo signal and a second value of T1 in the time-delay circuit before the integration of the second n-x echo signals.

Abstract: The timepiece (42) includes within the case (44) an electronic compass and a sighting device formed of two sighting marks (14, 15) arranged in the upper portion of the case (44) diametrically opposite each other and defining a reference axis of the case (44). The optical means formed by three light emitting diodes (54, 55, 56) are arranged on the surface of the case (44) in a peripheral region situated at six o'clock for warning or informing a user performing a sighting that the reference axis of the sighting device is aligned with a given azimuthal direction. In another embodiment, instead of the optical means, acoustic means or a buzzer are provided, capable of providing a vibration which is audible or perceptible by a user's body.

Abstract: A finished or semi-finished item in sintered zirconia is characterized by a metallic appearance obtained by placing a previously shaped and sintered zirconia item in its finished or semi-finished shape in an oven in which there is a plasma containing hydrogen, bringing the item to a temperature of around 800.degree. C. or more, and maintaining the item at this temperature for a period of time from around a quarter of an hour to three hours, preferably two hours.

Abstract: This invention provides protection against power supply failure, in particular of electronic circuits of timepieces powered by photovoltaic batteries. The invention comprises a continuous electric power supply comprising: an electrical continuous source (G) coupled to a power output (VDD, GND); energy storing means (6); and a reversible dc/dc electric converter (5) coupled both to the power output (VDD, GND) and to the energy storing means (6). The converter (5) comprises switching means (T1, T2, T3, T4) for modifying its configuration. The power supply storing means (6) comprise essentially a capacitor (C). Preferably, the reversible converter (5) is a dc/dc converter, the converter being a voltage multiplier in a first configuration and being a voltage divider in a second configuration.

Abstract: An angular speed measuring device comprises a rotating tuning fork transducer. First excitation electrodes excite the transducer to cause a first vibration in a first plane parallel to the planes of the principal faces of the transducer. The first vibration induces a second vibration in a plane perpendicular to the planes of the principal faces. The second vibration comprises a first component having an amplitude representative of the angular speed, and a second or parasite component. To avoid the distorting effects of the parasitic component of the second vibrations, the device is provided with a second set of excitation electrodes to excite a third vibration in the transducer, the third vibration being in phase opposition to the parasite component of the second vibration. Detection electrodes are provided for detecting vibrations in the direction perpendicular to the principal faces.

Abstract: The invention concerns a method for exciting and monitoring a piezoelectric motor (M1) in stepping mode, the motor having a resonance frequency (f.sub.R) and being supplied electrically at an excitation frequency (f.sub.E) during each operating step.The method is characterized in that it comprises a monitoring phase which extends at least over several successive steps of said motor and in which, for a present step of said motor, a determined excitation frequency value (f.sub.E +1) is used, the duration (t.sub.E +1) of the present step is measured, said duration (t.sub.E +1) is compared to the duration (t.sub.E) of the preceding step and, according to the result of this comparison, said excitation frequency value (f.sub.E +2) is corrected for the following step in a direction tending to reduce the duration of the step.A circuit is also described which enables the implementation of the method.

Abstract: Timepiece including:a spring (1a) housed in said barrel (1),an electric power generator (2) coupled to said barrel (1),a rectifier circuit (4) connected to said generator, anda regulator circuit (6) supplied by the direct voltage (Ua) from the rectifier circuit and intended to control the rotational speed of the generator (2).

Abstract: Timepiece comprising a mechanical movement which includes a barrel (8) driving a mechanism formed by a gear train, said timepiece comprising a device for indicating the power reserve comprising a resilient element (6) rotatively coupling in a mechanical manner two coaxial wheels (2,4) of said gear train and a disk (4) and a hand (42) rotatively coupled to said two coaxial wheels respectively and arranged so as to indicate an angular displacement between said hand (42) and a reference mark associated to said disk (40) for indicating the moment of force exerted by said barrel on said gear train, said moment of force being representative of the power reserve of the timepiece.

Abstract: The invention concerns an ultrasonic detection device intended to detect the presence of foreign bodies, on the surface of a window comprising a first sheet having a first thickness, comprising a transducer co-operating with a first face of said first sheet, said transducer being able to emit an ultrasonic signal of frequency f.sub.t and also able to receive a reflected ultrasonic signal on a second face of the first sheet, the variation in said reflected signal being representative of the presence or absence of foreign bodies on said second face facing said transducer. This device is characterized in that the frequency f.sub.t is selected to satisfy the following equation:f.sub.K /100.ltoreq..vertline.f.sub.t -f.sub.K .vertline..ltoreq.f.sub.K /10where f.sub.K =K.

Abstract: The device comprises a keyboard wherein each key is associated with an underlying sensor sensitive pad which controls the input of data associated with said key in response to an application of a finger on such key, such sensitive pads being closely set together within a closed contour (V.sub.1, V.sub.2 ; V'.sub.1, V'.sub.2) having, for a user, an upper part (V.sub.1) and a lower part (V.sub.2) respectively adjacent to first and second series of pads, such device being characterized in that the areas of the pads (10, 11, 12, 13; 7, 8, 9, .div.) of the first series are on the whole greater than the areas of the pads (3 to 9; 0, ., =, +) of the second series.