FR2733321A1 - DETECTOR UNIT OF INERTIA - Google Patents

Abstract

The present invention presents an inertia detector unit comprising first and second planar members supporting respective inertia detectors. Said inertia detector unit is characterized in that the planar elements (1, 1 ') are cored with surface formations (8, 10, 11) intended to engage with each other and to hold the elements. planes in an angular position relative to each other.

Description

DESCRIPTION

  The present invention relates to inertial sensor units of the type comprising first and second planar elements supporting respective inertial detectors.

  It is known to micro-machine semi-inertial detection devices

  conductors from monolithic parts made of a material such as silicon. These detection devices may be in the form of oscillating tuning forks having a detectable resonance when they are subjected to rotational accelerations (a semiconductor gyroscope shape) or cantilevered "spatula" masses presenting detectable displacements when they are subjected to translational accelerations (a form of semiconductor accelerometer). Parts of material in which these devices are micromachined are also known to be processed to incorporate the integrated digital and / or analog electrical drive, detection, processing and signaling devices necessary to make these parts, in the final phase, detection devices

  active semiconductor inertia or "chips".

  The previously described devices are micro-machined from essentially two-dimensional planar pieces of material, so that their resulting tuning forks and spatulas are in the plane of the material. Since the resulting tuning fork gyro detects rotation around its axis of symmetry and since the resulting spatula accelerometer detects normal acceleration relative to its plane of symmetry, an arrangement of these micro-machined devices from a workpiece material plane is typically unable to detect rotations around more than two

  axes or accelerations in more than one.

  In order to detect rotations around three orthogonal axes, two planar devices of this type are assembled in a three-dimensional shape. To detect accelerations in three orthogonal axes. three devices are assembled in a similar way. If inertial effects must be accurately measured, the units must be precisely aligned orthogonally. Since flat devices are small, it is difficult and expensive to build and maintain alignment

  accurate orthogonal during assembly.

  An object of the present invention is to provide a detector unit

  improved inertia and a method of manufacture.

  One aspect of the present invention provides an inertia detector unit of the type previously described, characterized in that the planar members are formed with surface formations for engaging with one another and maintaining the planar elements in a given angular position or relationship

  determined relative to one another or to each other.

  The planar elements are preferably assembled in an orthogonal arrangement. The surface formations may be located to an edge or edge of the planar members and may be provided by alternating projections and recesses along an edge or edge of each planar member. The surface formations in at least one of the planar elements may be provided by at least one opening in

the plane element.

  The unit preferably comprises three plane elements orthogonally connected to one another by engagement or mutual engagement of the surface formations. The detectors are preferably semiconductor or semi-conductive vibrating inertia detectors and each planar element may include two inertia detectors arranged at right angles to one another. Detectors may include an acceleration sensor. The detectors are preferably manufactured or machined from the material of the planar elements. The flat elements

  can also support associated electronic devices for detectors.

  The planar elements may be electrically interconnected with each other at points or locations adjacent to a line of intersection of the

flat elements.

  An inertial sensor unit according to the present invention will now be described in detail by way of example, with reference to the accompanying drawings in which: FIG. 1 is a flat view of a detection chip with shapes jointing with overlapped edges; Figure 2 is a plan view of a chip having a plurality of detectors and mortise and tenon join formations; Figure 3 is a perspective view of a unit of three sensor chips shown in Figure 1; Figure 4 is an exploded perspective view of a unit of three sensor chips shown in Figure 2; Figure 5a is a perspective view of a unit of six sensor chips shown in Figure 2; Fig. 5b is a perspective view of a plinth support chip for mounting the unit shown in Fig. 5a; Figure 5c is a perspective view of the unit shown in Figure 5a mounted on the support chip shown in Figure 5b; Figure 6 is an exploded perspective view of the seal between the sensor chips shown in Figure 1; Figure 7 is a sectional view of an electrical connection between two detection chips; Figure 8 is a perspective view of an alternative electrical connection between two detection chips; Figure 9a is an exploded perspective view before mounting the joint shape of two sensor chips shown in Figure 2; Figure 9b is an exploded perspective view of the complete seal between the two sensor chips shown in Figure 9a; Fig. 10a is an exploded perspective view of an alternative arrangement of a joint shape with electrical connectors of the sensing chip shown in Fig. 1 prior to mounting; Figure 10b is an exploded perspective view of the complete seal between two sensor chips shown in Figure 10a; Figure 1a is an exploded perspective view of two locked detection chips of the type shown in Figure 1; Fig. 11b is an exploded perspective view of an electrical connection component for joining the locked detection chips shown in Fig. 1a; and Fig. 1c is an exploded perspective view of the complete seal between the two locked detection chips shown in Fig. 1a, electrically connected by the connection component shown in Fig. 1b. With reference to FIG. 1, we see a flat silicon chip 1

  incorporating in its central zone a rotational speed detector 2 in micro tuning fork.

  machined in an integrated way. The detector 2 is sensitive to rotation accelerations around an axis X parallel to the arms of the tuning fork and lying in the plane of vibration. The detector 2 is subjected to excitation drivers 3 and resonance detectors connected by electrical rails 5 to an integrated processing device 6, which in turn is connected to electrical connection pads 7 at the edge. of the chip. The edge of the chip has been micro-machined using the same technique or method used to form the tuning fork 2 to dig overlapping engaged edge joining formations 8 during the same operation. 8 forms are a

  series of projections and rectangular recesses along the edges of the chip 1.

  Referring now to FIG. 2, there is shown an alternative flat silicon chip configuration 1 'incorporating an inertia sensor arrangement comprising two integrally micro-machined pitch detectors 2' arranged at right angles to each other. detect rotational accelerations around the X and Y axes, respectively. Chip 1 'also includes an integrated micro-machined spatula linear acceleration sensor 9 for detecting translation accelerations in the direction of a Z axis (not shown) perpendicular to the detector plane. Next to its edge, the chip 1 'has been micro-machined according to the same method used to form the tuning forks 2' and the spatula 9 in order to dig mortise holes 10 inside its body and on its corresponding edges. tongues 11

  protruding, each with electrical connection pads 7 (see Figure 7).

  FIG. 3 represents a unit of three identical planar silicon chips 1 represented in FIG. 1, illustrating the locking of the overlapping edge-joined edge forms 8 of each chip in order to create a three-dimensional detection device capable of detecting rotations around orthogonal axes X, YetZ. In Figure 4, we see an alternative embodiment of the invention showing three planar silicon chips 1 'of Figure 2, before mounting. After mounting, their mortise and tenon join shapes 10 and 11 lock to create a three-dimensional detection device capable of providing dual rotational acceleration detection in each of the three X, Y and Z axes through detectors 2 'in tuning fork aligned differently. The unit may also provide a single translation acceleration detection in each of the three identical X, Y and Z axes by means of spatula detectors 9. It will be appreciated that other detectors could be integrated with each chip, co-aligned or differently oriented, in order to further increase the multiplicity and / or redundancy of the detection capabilities of

unity in each axis.

  Figure 5a shows a closed unit 12 of six silicon chips 1 'shown in Figure 2 providing quadruple rotation detection and double translation detection, in all three axes. A skirting support chip 13 for mounting the unit 12 is shown in Figure 5b; it has recesses 14 for receiving the tongue tongues 11 of the unit 12, as shown in Figure 5c. The support chip 13 has connection pads 15 aligned to accept electrical connections with the unit 12 and rails 16 and terminal pads 17 configured to electrically connect the unit.

  complete with other electrical devices (not shown).

  FIG. 6 shows the paired join shapes of two silicon chips 1 shown in FIG. 1 illustrating the proximity of the electrical connection pads 7 in the join shapes 8 of each chip 1. The buffers 7 on the two chips could be connected electrically by a solder plug 18, as

  as shown in Figure 7, or by cable guying, as shown in Figure 8.

  FIG. 9a shows the corresponding mortise surface formations 10 and ten on two sensor chips 1 'shown in FIG. 2. The electrical connection pads 7 in the mortise and tenon join surfaces are intended to come into contact with each other. with each other when the chips are matched. The geometry of the mortise 10 and tenon 11 is bevelled so that when assembled as shown in FIG. 9b, a residual tight fit stress maintains contact between the electrical connection pads.

respective 7.

  FIG. 10A shows an overlapped edge-joined edge shape of the silicon chip 1 shown in FIG. 1 illustrating electrically conductive tenons 7 'exposed sacrificially by the photo-corrosion removal process. used to generate joined-edge join shapes

overlapping.

  When the two chips 1 are assembled with each other, the pins 7 'on one chip are twisted and come into contact with the pads on the overlapped edge join formation of the other chip, as shown in FIG. 1Ob, so that

  the chips are electrically interconnected.

  FIG. 1a shows the locked and assembled overlapped-edge joint shapes 8 of two paired silicon chips 1 shown in FIG. 1, illustrating an alternative embodiment of the electrically-conductive pads 7 arranged externally and rails 5. The buffers 7 are interconnected by an additional electrical unit component 20 comprising a nonconductive support material with electrically conductive posts 7 "selectively connected by rails 5". The tenons 7 "protrude at right angles and are placed so as to come into contact with the pads 7 on the chips 1, as shown in FIG. 1c, so

  that the electrical connection is established between the circuits on the two chips.

  Other forms of connection could be used. Flat chips do not have to be orthogonally assembled. If desired, they can be assembled at other angles relative to each other. Although it is preferred that the inertia sensors be formed from the material of the planar elements themselves, it would be possible to separately form them and subsequently attach them to mounting panels formed with the formation formations.

surface in engagement.

  The rigidity and / or structural integrity of the units depends on the geometry of the joint shapes and the nature of the electrical connections. Traditional welding or potting techniques can be used to

  improve the rigidity of the structure.

  Detector geometries in the planar devices may be varied during or after formation and prior to assembly, so as to avoid vibration resonance or other undesirable cross-coupling effects between the detectors.

Claims (12)

  An inertial sensor unit comprising first and second planar members supporting respective inertia sensors, characterized in that the planar members (1, 1 ') are formed with surface formations (8, 10, 11). intended to engage with each other and to maintain planar elements in a   angle relative to each other or to each other.   Unit according to claim 1, characterized in that the elements   planes (1, 1 ') are orthogonally assembled.   3. Unit according to claim 1 or 2, characterized in that the   surface formations (8, 10, 11) are located towards an edge of the planar elements.   4. Unit according to claim 3, characterized in that the surface formations are provided by projections and recesses (8) alternated along an edge plane elements (1).   Unit according to one of the preceding claims, characterized in that   that a surface formation in at least one plane element (1 ') is provided by at least   an opening (10) in the planar element.   Unit according to one of the preceding claims, characterized in that   that the unit includes three planar elements (1, 1 ') orthogonally assembled together   with others by engagement or engaging surface formations (8, 10, 11).   7. Unit according to one of the preceding claims, characterized in that   the detectors are semiconductor vibrating inertia detectors (2, 2 ').   8. Unit according to claim 7, characterized in that each planar element includes two vibrating inertia detectors (2 ') arranged at right angles to each other. report to the other.   Unit according to one of the preceding claims, characterized in that   the detectors include an acceleration sensor (9).   Unit according to one of the preceding claims, characterized in that   the detectors (2, 2 ') are machined from the material of the planar elements (1, 1').   Unit according to one of the preceding claims, characterized in that   the planar elements (1, 1 ') support electronic devices (3, 4, 5, 6)   associated for the detectors (2, 2 ').   Unit according to one of the preceding claims, characterized in that   planar elements (1, 1 ') are electrically interconnected with each other.   others at locations (7) adjacent to a line of intersection of planar elements.