ELECTRONIC DEVICE

An arrangement is provided reduces deformation induced by vibration movements in electronic devices such as Micro Inertial Measurement systems. The result is achieved by the use and particular arrangement of additional printed circuit boards.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to European Patent Application No. 22204378.8, filed Oct. 28, 2022, the contents of which are hereby incorporated by reference in its entirety.

TECHNICAL FIELD

This disclosure relates to electronic devices, and, more particularly, to Micro Inertial Measurement Units. The present disclosure further concerns measurement units where chips are mounted on multiple surfaces which are perpendicular to each other.

BACKGROUND

Electronic chips, which may also be called dies, are usually prepared by manufacturing various electronic structures on a substrate and cutting the substrate into small, chip-size pieces. Each chip can then be placed inside a protective package which forms an enclosure where the chip is protected from the surrounding environment. The chip can be mechanically attached to a support structure inside the enclosure, and electrically connected to contacts which extend outside of the enclosure. The packaged chip thereby forms an electronic component which can be mounted on a printed circuit board (PCB). Electronic components typically comprise at least one electronic chip and a package.

Microelectromechanical (MEMS) devices are electronic components that combine mechanical and electrical parts. They can have either simple or complex structures systems with various moving elements. MEMS devices include different type of sensors such as temperature sensors, pressure sensors and vibration sensors. Other examples of MEMS sensors are accelerometers, gyroscopes and magnetometers which are usually used in Micro Inertial Measurements Units (IMU).

A Micro Inertial Measurements Unit is an electronic device that measures the force, orientation, and/or angular velocity of an object to which it is attached. It usually comprises a combination of MEMS accelerometers, gyroscopes and sometimes magnetometers. The IMU measures linear acceleration using accelerometers and rotational rates using gyroscopes. When magnetometers are included in IMUs, they can alternatively measure the magnetic field. The accelerometers, gyroscopes and magnetometers are connected to PCBs which can be attached to each other according to various geometric arrangements.

FIG.1illustrates schematically an existing Micro Inertial Measurement system, disclosed in U.S. Patent Publication No. 2013/0111993 A1, where the sensing support is composed of three pieces of a gyro circuit board100,101and102, which are perpendicular to each other. As shown, the device comprises three one-axis gyroscopes103that are arranged on the circuit boards100,101and102. A problem with the use of such structures is that when the device undergoes vibrational movements due to applied accelerations, the PCBs experience mechanical deformation which directly impacts the MEMS components attached to them. Consequently, the components may be oriented in the wrong direction or may be damaged affecting thereby the measurement accuracy of the device.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present disclosure is to provide an electronic device that address the problems described above. In particular, the exemplary aspects disclosed therein reduce the deformation of the components induced by vibrational movements.

According to an exemplary aspect, an electronic device is provided that includes a first circuit board that defines a horizontal xy-plane and a vertical z-direction that is perpendicular to the xy-plane, the first circuit board having an inside surface and an outside surface; a first set of dies connected to the first circuit board; a second circuit board that defines an xz-plane and a y-direction that is perpendicular to the xz-plane, the second circuit board having an inside surface and an outside surface; a second set of dies connected to the second circuit board; a third circuit board that defines a yz-plane and a x-direction that is perpendicular to the yz-plane, the third circuit board having an inside surface and an outside surface; and a fourth circuit board that is parallel to the third circuit board and is attached to the first and the second circuit boards. In this aspect, the first, the second and the third circuit boards are attached to each other.

According to an exemplary aspect, an electronic device is provided that includes a first circuit board that defines a first plane and has an inside surface and an outside surface; a first set of dies connected to the inside surface of the first circuit board; a second circuit board that defines a second plane orthogonal to the first plane and having an inside surface and an outside surface; a second set of dies connected to an inside surface of the second circuit board; a third circuit board that defines a third plane that is orthogonal to the first and second planes and has an inside surface and an outside surface; and a fourth circuit board that is parallel to the third circuit board and is attached to the first and the second circuit boards. In this aspect, the first, the second and the third circuit boards are attached to each other.

The exemplary aspects of the present disclosure are premised on the reducing the amount of deformation by increasing the strength of the housing. This is achieved by arranging in perpendicular positions at least three vertical PCBs attached to a horizontal PCB. Multi-axis detection is achieved by using multiple sensors, and reliability is improved by using multiple sensors on the same axis. This configuration provides new improvements in IMU device reliability.

DETAILED DESCRIPTION

The disclosure describes an electronic device comprising a first circuit board where the first circuit board defines a horizontal xy-plane (e.g., a first plane) and a vertical z-direction which is perpendicular to the xy-plane. The first circuit board has an inside surface and an outside surface. The device also comprises a first set of dies which are connected to the first circuit board. The device further comprises a second circuit board which defines a xz-plane (e.g., a second plane) and a y-direction which is perpendicular to the xz-plane. The second circuit board also has an inside surface and an outside surface, and the device comprises a second set of dies which are connected to the second circuit board. The electronic device further comprises a third circuit board which defines an yz-plane (e.g., a third plane) and a x-direction which is perpendicular to the yz-plane. The third circuit board has an inside surface and an outside surface. The first, the second and the third circuit boards are attached to each other. The electronic device further comprises a fourth circuit board which is parallel to the third circuit board and attached to the first and the second circuit board.

The device is configured to be mounted, for example, onto an external object. Any side of the device could be attached to the surface of the external object according to the exemplary aspect. Moreover, the external object could be oriented in any manner. For purposes of this disclosure, terms such as “bottom” and “top”, “above” and “below” do not refer to the orientation of the device with regard to the direction of earth's gravitational field either when the device is manufactured or when it is in use. Moreover, the expressions “inside surface” and “outside surface” only refer to the two sides of a particular circuit board and their positions within the device. The inside surface of the circuit board is the side of the circuit board facing the center of the device, whereas the outside surface of the circuit board is the side which faces the surrounding of the device. The expression “horizontal” refers here to a position that is parallel to the xy-plane, whereas the expression “vertical” refers to a position that is perpendicular to the xy-plane.

For purposes of this disclosure, the plane defined by the x- and y-axes is parallel to the plane of the first printed circuit board to which dies are attached. The direction defined by the z-axis is perpendicular to the same circuit board plane. The plane defined by the x- and z-axes is parallel to the second printed circuit board to which dies are attached. The direction defined by the y-axis is perpendicular to the same circuit board plane. The plane defined by the y- and z-axes is parallel to the planes of the third and fourth circuit boards to which dies are attached. The direction defined by the x-axis is perpendicular to the same circuit boards planes.

FIG.2aillustrates schematically an example of the geometry that may be formed by the printed circuit boards in such device according to an exemplary aspect. As shown, the device comprises a first horizontal circuit board200and additional three vertical circuit boards. The second circuit board201, the third circuit board202and the fourth circuit board204are attached to the horizontal printed circuit board200. The third circuit board202is parallel to the fourth circuit board204. The second, the third, and fourth circuit boards can form a U-shape in the xy-plane and all the circuit boards that are attached to each other are perpendicular to each other. In other words, the circuit boards are arranged in a three-dimensional shape where every two meeting boards form a 90° angle on the device side which faces the center. One circuit board may also extend past an adjacent circuit board forming a 90° angle on the device side which faces the surrounding. Mounting at right angles can be performed by a variety of methods that include, but are not limited to, soldering, screwing, inserting, or gluing the circuit boards together. This mounting geometry provides structural rigidity which strengthens the housing.

FIG.2billustrates schematically another example of the geometry that can be formed by the printed circuit boards in such device according to an exemplary aspect. The device comprises a horizontal first circuit board210and additional four vertical circuit boards. The second circuit board211, the third circuit board212and the fourth circuit board214are attached to the first printed circuit board210. The device may comprise a fifth circuit board215parallel to the second circuit board211and attached to the third212and the fourth circuit boards214. The fifth circuit board has an inside surface and an outside surface. The second circuit board211is parallel to the fifth circuit board215, whereas the third circuit board212is parallel to the fourth circuit board214. In this aspect, all meeting circuit boards are perpendicular to each other. In other words, the circuit boards form a three-dimensional structure where the vertical boards are arranged in a rectangle/square-like shape. In an exemplary aspect, one circuit board may also extend past an adjacent circuit board forming a 90° angle on the device side which faces the surrounding. Reference numbers210,211,212, and214inFIG.2bcorrespond to reference numbers200,201,202and204, respectively, inFIG.2a.

FIG.3illustrates schematically an electronic device comprising several printed circuit boards forming a U-shape in the xy-plane and dies connected to the printed circuit boards according to an exemplary aspect. The device may be a Micro Inertial Measurement Unit built using FP4, or FR4, or FR5, or CEM, or LTCC, or flexible PCB material, or any combination of these materials. It is noted that these options can apply to all embodiments in this disclosure. The device comprises a horizontal first circuit board300and three additional vertical circuit boards. The second circuit board301, the third circuit board302and the fourth circuit board304are attached to the top side of the horizontal first printed circuit board300, and the third circuit board302is parallel to the fourth circuit board304. The device further comprises a first set of dies306which are connected to the first circuit board300, and a second set of dies307which are connected to the second printed circuit board301. The first set of dies306may comprise at least one gyroscope or at least one acceleration sensor. The second set of dies307may also comprise at least one gyroscope or at least one acceleration sensor. For example, the first set of dies306may comprise a gyroscope308and an acceleration sensor309and the second set of dies307may also comprise a gyroscope308and an acceleration sensor309. Reference numbers300,301,302, and304inFIG.3correspond to reference numbers200,201,202and204, respectively, inFIG.2a.

The device may further comprise a third set of dies and the third set of dies is connected to the third circuit board.FIG.4aillustrates schematically an electronic device comprising several printed circuit boards forming a U-shape in the xy-plane and dies connected to the printed circuit boards according to the exemplary aspect. In particular, the device comprises a horizontal first circuit board400and three additional vertical circuit boards. The second circuit board401, the third circuit board402and the fourth circuit board404are attached to the top side of the horizontal first printed circuit board400, and the third circuit board402is parallel to the fourth circuit board404. The device further comprises a first set of dies406which are connected to the first circuit board400, a second set of dies407which are connected to the second printed circuit board401, and a third set of dies4010which are connected to the third printed circuit board402. For example, the first set of dies406may comprise a gyroscope408and an acceleration sensor409. The second set of dies407may also comprise a gyroscope408and an acceleration sensor409. The third set of dies4010may also comprise a gyroscope and an acceleration sensor409. Reference numbers400,401,402,404,406,407,408and409inFIG.4acorrespond to reference numbers300,301,302,304,306,307,308and309, respectively, inFIG.3.

The device may further comprise a fourth set of dies and the fourth set of dies is connected to the fourth circuit board.FIG.4billustrates schematically an electronic device comprising several printed circuit boards forming a U-shape in the xy-plane and dies connected to the printed circuit boards according to an exemplary aspect. The device comprises a horizontal first circuit board410and three additional vertical circuit boards. The second circuit board411, the third circuit board412and the fourth circuit board414are attached to the top side of the horizontal first printed circuit board410, and the third circuit board412is parallel to the fourth circuit board414. The device further comprises a first set of dies416which are connected to the first circuit board410, a second set of dies417which are connected to the second printed circuit board411, a third set of dies4110which are connected to the third printed circuit board412, and a fourth set of dies4111which are connected to the fourth printed circuit board414. The dies may for example be gyroscopes418and acceleration sensors419. Reference numbers410,411,412,414,416,417,418,419and4110inFIG.4bcorrespond to reference numbers400,401,402,404,406,407,408,409and4010, respectively, inFIG.4a.

It is noted that the first set of dies may be connected to the inside surface of the first circuit board, the second set of dies may be connected to the inside surface of the second circuit board, the third set of dies may be connected to the inside surface of the third circuit board and the fourth set of dies may be connected to the inside surface of the fourth circuit board. Alternatively, one or more sets of dies could be placed on the outside surface of a circuit board.

Each of the first, second, third and fourth sets of dies can comprise one or more MEMS dies. For example, in one possible embodiment, when used in IMUs, the first set of dies may comprise a gyroscope and/or an acceleration sensor and the second set of dies may also comprise a gyroscope and/or an acceleration sensor. As a first additional option, the third set of dies may also comprise a gyroscope and/or an acceleration sensor. As a second additional option, the fourth set of dies may also comprise a gyroscope and/or an acceleration sensor.

It is further noted that any gyroscope presented in this disclosure may be a single-axis or, 2-axis or 3-axis gyroscope and any acceleration sensor may be a single-axis or, 2-axis or 3-axis acceleration sensor. Any gyroscope may measure rotation rates about at least one axis. Correspondingly, any acceleration sensor may measure acceleration along at least one axis. This applies to all embodiments in this disclosure.

FIG.5illustrates schematically an electronic device comprising several printed circuit boards forming a U-shape in the xy-plane and dies connected to the printed circuit boards according to an exemplary aspect. In particular, the device comprises a horizontal first circuit board500and three additional vertical circuit boards. The second circuit board501, the third circuit board502and the fourth circuit board504are attached to the top side of the horizontal first printed circuit board500, and the third circuit board502is parallel to the fourth circuit board504. The device further comprises a first set of dies506which are connected to the first circuit board500, a second set of dies507which are connected to the second printed circuit board501, a third set of dies5010which are connected to the third printed circuit board502, and a fourth set of dies5011which are connected to the fourth printed circuit board504. For example, in this embodiment the first set of dies506may be a gyroscope508, the second set of dies507may also be a gyroscope508, the third set of dies5010may be an acceleration sensor509, and the fourth set of dies5011may also be a gyroscope508. In this embodiment, the gyroscopes may be single-axis gyroscopes and the acceleration sensor may be a 3-axis acceleration sensor. Reference numbers500,501,502,504,506,507,508,509,5010and5011inFIG.5correspond to reference numbers410,411,412,414,416,417,418,419,4110and4111, respectively, inFIG.4b.

In another possible embodiment, the first set of dies may be a gyroscope and a 3-axis acceleration sensor, the second set of dies may be only a gyroscope, and the third set of dies may be only a gyroscope. To ensure measurement accuracy, redundant dies may as well be used. For example, the first set of dies may comprise at least two gyroscopes and one acceleration sensor, the second set of dies may comprise at least two gyroscopes and one acceleration sensor, the third set of dies may comprise at least one gyroscope, and the fourth set of dies may comprise at least one gyroscope.FIG.6illustrates schematically an example of such electronic device.

In particular, the exemplary device may be a Micro Inertial Measurement Unit that comprises a horizontal first circuit board600, three additional vertical circuit boards forming a U-shape in the xy-plane and eight dies connected to the printed circuit boards. The second circuit board601, the third circuit board602and the fourth circuit board604are attached to the top side of the horizontal first printed circuit board600, and the third circuit board602is parallel to the fourth circuit board604. The device comprises a first set of dies606which are connected to the first circuit board600, a second set of dies607which are connected to the second printed circuit board601, a third set of dies6010which are connected to the third printed circuit board602and a fourth set of dies6011which are connected to the fourth printed circuit board604. In this embodiment, the first set of dies606may for example be a first gyroscope608, a second gyroscope608and a first acceleration sensor609. The first and second gyroscopes608may be single-axis gyroscopes whereas the acceleration sensor609may be a 3-axis acceleration sensor. The second gyroscope may be used to redundantly backup the first gyroscope. The second set of dies607may be a third gyroscope608, a fourth gyroscope608and a second acceleration sensor609. The third and fourth gyroscopes608may be single-axis gyroscopes, and the second acceleration sensor609may be a 3-axis acceleration sensor. The fourth gyroscope may be used to redundantly backup the third gyroscope. The third set of dies6010may be a fifth single-axis gyroscope608, and the fourth set of dies6011may be a sixth single-axis gyroscope608. The sixth gyroscope may be used to redundantly backup the fifth gyroscope. The second acceleration sensor may be used to redundantly backup the first acceleration sensor. Reference numbers600,601,602,604,606,607,608,609,6010and6011inFIG.6correspond to reference numbers500,501,502,504,506,507,508,509,5010and5011, respectively, inFIG.5.

Moreover, the device may comprise a fifth printed circuit board parallel to the second circuit board and attached to the third and fourth circuit boards, where all meeting circuit boards are perpendicular to each other. The device may also comprise a fifth set of dies and the fifth set of dies are connected to the fifth circuit board. The fifth set of dies may be connected to the inside surface of the fifth circuit board. Alternatively, the fifth set of dies could be placed on the outside surface of the fifth circuit board.

FIG.7aillustrates a top view of a device comprising three vertical circuit boards attached to a horizontal printed circuit board under the effects of vibrational movements which occur in one direction. When the device is not subject to any vibrational forces, the vertical circuit boards form a U shape in the xy-plane. The drawings on the left show the shape that vertical printed circuit boards may take when the device undergoes vibrations along the x-axis. Vibration movements may induce deformations which may lead to the shift of the parallel vertical third and fourth printed circuit boards from their initial positions towards the left and the right. In other words, a change in angle between the second and third printed circuit board as well as between the second and fourth circuit boards may take place in a repetitive manner. The initial right angle of 90° may change back and forth between values below 90° and above 90°. The drawings in the center show the shape that the vertical printed circuit boards may take when the device undergoes vibrations along the y-axis. Such movements may induce a deformation of the second printed circuit board along the y-axis which may lead to its bending towards the center of the device and away from the center of the device in a cyclic way. The deformation of the second printed circuit board may resemble then an alternation of a “smile” and a “sad” like shapes. The drawings on the right show the other shape that the vertical printed circuit boards may also take when the device undergoes stronger vibrations along the y-axis. Such vibration movements may induce deformations which may lead to the simultaneous shift of the parallel vertical third and fourth printed circuit boards from their initial positions towards the left and the right and to the bending of the second printed circuit board along the y-axis towards the center of the device and away from the center of the device.

FIG.7billustrates a top view of a device comprising three vertical circuit boards attached to a horizontal printed circuit board under the effects of vibrational movements which occur in two directions. When the device is not subject to any vibrational forces, the vertical circuit boards form a U shape in the xy-plane. However, when the device undergoes vibrational movements that occur along the x-axis and the y-axis at the same time, deformation of the U shape may take place. This deformation may involve the simultaneous bending of the second circuit board towards or away from the center of the device and a shift of either the third circuit board, or the fourth circuit board, or the third and the fourth circuit board together from their initial position, depending on the strength of the vibrations.

In general, it is noted that the exemplary embodiments described above are intended to facilitate the understanding of the present invention and are not intended to limit the interpretation of the present invention. The present invention may be modified and/or improved without departing from the spirit and scope thereof, and equivalents thereof are also included in the present invention. That is, exemplary embodiments obtained by those skilled in the art applying design change as appropriate on the embodiments are also included in the scope of the present invention as long as the obtained embodiments have the features of the present invention. For example, each of the elements included in each of the embodiments, and arrangement, materials, conditions, shapes, sizes, and the like thereof are not limited to those exemplified above and may be modified as appropriate. It is to be understood that the exemplary embodiments are merely illustrative, partial substitutions or combinations of the configurations described in the different embodiments are possible to be made, and configurations obtained by such substitutions or combinations are also included in the scope of the present invention as long as they have the features of the present invention.