Centre Electronique Horloger S. A.

Centre Suisse D'electronique Et De Microtechnique Sa

Csem Centre Suisse D'electronique Et De Microtechnique Sa

Jean W Hermann

Claude Bourgeois

Hubert Choffat

An electronic device (1) has a substrate (2) of monocrystalline silicon on which is an integrated circuit (3). The integrated circuit is an oscillator containing a resonator, a maintenance circuit to cause the vibration of the resonator, and a frequency division chain. The maintenance circuit as well as the division chain are manufactured as CMOS circuits. The resonator is an integrated resonator (4) formed of a body cut out in a delimited surface part of reduced thickness (14) of the substrate (2), of a thin layer of piezoelectric material (10) deposited on at least a part (6) of the body, and of a thin metallic layer (11) deposited on the piezoelectric layer (10) so as to form an electrode.

Electronic device comprising an integrated time base

A micromachined measuring cell is adapted to be mounted on a support and has a measuring sensor (121) and an assembly structure (120) distinct from one another and associated with each other by a connecting arm (128). At least one part element (103b) of the assembly structure, one part (133) of the connecting arm and one part (103a) of the sensor (121) are produced as one single piece. The assembly structure (120) of this measuring cell is preferably in the shape of a frame surrounding the sensor (121).

Micromachined measuring cell with arm supported sensor

A thin quartz plate having opposite major surfaces, each of the opposite major surfaces having a geometrical shape symmetrical or antisymmetrical with respect to an axis of reference; and X, Y and Z crystallographic directions corresponding to electrical, mechanical and optical axes, respectively, of the quartz plate, wherein the axis of reference forms an angle .psi. with said X axis, and the major surfaces form an angle .theta. with a plane defined by said X and Y axes, the angles .theta. and .psi. being chosen such that the first order frequency-temperature coefficient (.alpha.) of the quartz resonator is substantially 0, and the second order frequency-temperature coefficient (.beta.) of said quartz resonator is substantially 0. The shape of the resonator may be rectangular, square, polygonal, circular or elliptical. The resonator is fixed on a supporting base by means of at least one pair of connecting arms located on the extension of a nodal line. The resonator of the invention finds application in the field of relatively low frequency miniature resonators suitable for encapsulation.

Quartz resonator vibrating in a fundamental torsion mode

A piezoelectric resonator containing two rectangular parallelepipedal slices including N and M base structures, respectively, wherein N and M are integers. The two rectangular parallelepipedal slices each include at least one base structure shaped as a thin crystal slice of piezoelectric material in the form of a rectangular parallelepiped. A non-resonant arm connects the two rectangular parallelepipedal slices in juxtaposition in a single plane. An embedding zone is connected to the arm through a connection zone so as to fix the resonator outside a center thereof. Electrodes are disposed on opposite surfaces of the two rectangular parallelepipedal slices and are polarized to excite preferentially the Nth harmonic of a fundamental contour vibration mode in each base structure, and to produce respective extension modes in the two rectangular parallelepipedal slices in a direction perpendicular to an axis of the non-resonant arm.

High frequency piezoelectric resonator

A piezoelectric resonator formed as a thin parallelepipedic quartz plate whose width is arranged along the electric axis X of the crystal, the length along an axis Y' and the thickness along an axis Z', wherein the axes Y' and Z' form an angle approximately equal to 24.degree. with the mechanical axis Y and the optical axis Z of the crystal, respectively, and the ratio w/l of its width to its length is approximately equal to 0.64.

Piezoelectric resonator

Axes X', Y' and Z' of a resonator are established from the axes X, Y and Z of a quartz crystal by virtue of two rotational movements through angles .phi. and .theta., respectively. The resonator is energized to vibrate in accordance with the fundamental torsional mode. The angles of cut .phi. and .theta. are such that the first-order temperature coefficient is zero. The torsional mode may be coupled to a flexural mode in order to render the second-order temperature coefficient zero. The fork tines extend in the X' direction. In other embodiments the tines extend in the Y' direction and the rotation .phi. and .theta. are about the X and Z' axes, respectively.

Cut angles for tuning fork type quartz resonators

A ZT-cut quartz crystal resonator comprises two thin rectangular plates connected together by at least one resonant arm which itself is connected to a support zone by a linking bar. A pair of electrodes is provided on the quartz resonator for receiving alternating electrical signals of opposite polarity for effecting in-phase contour-mode vibration of the plates while making the arms to vibrate in opposite phase to the plates.

ZT-Cut piezo-electric resonator

The resonator according to the invention comprises at least one quartz crystal in the form of a rectangular thin plate, of which the length l is directed along an axis X', the width w along an axis Y' and the thickness t along an axis Z', and which vibrates in a contour mode. The axis Z' is situated in the plane of the electrical axis X and optical axis Z of the crystal and forms with the axis Z an angle .phi. such that

Piezo-electric quartz resonator

The invention relates to piezoelectric resonators, and more particularly to piezoelectric resonators comprising a DT- or CT-cut quartz plate vibrating torsionally about its longitudinal axis which is the electrical axis X of the quartz crystal. The width of the plate b, extending along the Z'-axis, and its thickness h extending along the Y'-axis are linked by the relation

Torsional mode CT or DT cut quartz resonator

A piezoelectric resonator, particularly for electronic wrist watches, comprises an elongated piezoelectric crystal rod that oscillates in length-extension. Opposite faces of the rod are partially metallized; and short wires are secured tangentially to these metallized surfaces midway of the length of the rod. The wires extend perpendicular to the length of the rod and are secured at their other ends to metallized opposite surfaces of an elongated ceramic support which is parallel to and of about the same size and shape as the rod. The support also has metallized end faces which are secured to the inner ends of support wires that pass through a casing in sealed relationship and mount the support and rod in spaced relation from the casing.

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Neuchatel, Switzerland

Jean W Hermann