Sensor shift flexure arrangements for improved signal routing
Various embodiments include sensor shift flexure arrangements for improved signal routing. For example, a camera with sensor shift actuation may include a flexure for suspending an image sensor from a stationary structure of the camera, and for allowing motion of the image sensor enabled by one or more actuators of the camera. The flexure may be configured to convey electrical signals between the image sensor and a flex circuit in some embodiments. According to some embodiments, the flexure may include a stack of layers comprising an electrical grounding portion that has an additional conductive layer adjacent to a base layer, which may reduce the overall resistivity of a ground current return path. In some embodiments, the flexure may additionally or alternatively include an impedance adjusting feature configured to adjust the impedance of an electrical signal pad used to connect the flexure with another component of the camera.
1. A camera, comprising:
a lens group;
an image sensor;
an actuator to move the image sensor relative to the lens group; and
a flexure that suspends the image sensor from a stationary structure of the camera and that allows motion of the image sensor enabled by the actuator, the flexure comprising:
a plurality of layers stacked in a direction orthogonal to an image plane defined by the image sensor, the plurality of layers comprising:
an electrical grounding portion, comprising:
a base layer comprising a metal alloy; and
a conductive layer adjacent the base layer, wherein the conductive layer provides a ground plane that reduces ground current resistance of the flexure, relative to a ground current resistance of the base layer without the conductive layer.
2. The camera of claim 1 , wherein:
the conductive layer is a first conductive layer; and
the plurality of layers further comprises:
a second conductive layer;
a dielectric layer positioned, in the direction orthogonal to the image plane, between the first conductive layer and the second conductive layer; and
a via configured to convey electrical current from the second conductive layer to the first conductive layer, wherein the via extends, in the direction orthogonal to the image plane, through the dielectric layer.
3. The camera of claim 1 , wherein the conductive layer is a copper layer having a thickness ranging from about 2 microns to about 30 microns.
4. The camera of claim 1 , wherein the plurality of layers further comprises:
a signal trace interconnect portion, comprising:
an electrical signal pad for attaching the flexure with one or more other components; and
an intermediate portion, comprising:
a dielectric layer positioned, in the direction orthogonal to the image plane, between the conductive layer of the electrical grounding portion and the signal trace interconnect portion; and
wherein a portion of the electrical grounding portion defines an impedance adjusting feature comprising (i) a void or (ii) a cavity that is at least partially filled with an insulating material, and wherein the impedance adjusting feature is positioned along an axis that intersects with the signal trace interconnect portion.
5. The camera of claim 4 , wherein:
the conductive layer is a first conductive layer;
the intermediate portion comprises:
an adhesion layer adjacent the first conductive layer; and
a dielectric layer adjacent the adhesion layer;
the signal trace interconnect portion further comprises:
a second conductive layer defining an electrical signal trace;
wherein the electrical signal pad is positioned adjacent the electrical signal trace; and
the impedance adjusting feature is configured to increase the impedance of the electrical signal pad to a target impedance that is closer to the impedance of electrical signal trace, relative to an impedance of the electrical signal pad if the flexure did not include the impedance adjusting feature.
6. The camera of claim 5 , wherein the impedance adjusting feature is an empty void.
7. The camera of claim 5 , wherein the impedance adjusting feature is an epoxy-filled cavity.
8. A device, comprising:
one or more processors;
memory storing program instructions executable by the one or more processors to control operations of a camera; and
the camera, comprising:
a lens group;
an image sensor;
an actuator to move the image sensor relative to the lens group; and
a flexure that suspends the image sensor from a stationary structure of the camera and that allows motion of the image sensor enabled by the actuator, the flexure comprising:
a plurality of layers stacked in a direction orthogonal to an image plane defined by the image sensor, the plurality of layers comprising:
an electrical grounding portion, comprising:
a base layer comprising a metal alloy; and
a conductive layer adjacent the base layer, wherein the conductive layer provides a ground plane that reduces ground current resistance of the flexure, relative to a ground current resistance of the base layer without the conductive layer.
9. The device of claim 8 , wherein:
the conductive layer is a first conductive layer; and
the plurality of layers further comprises:
a second conductive layer;
at least one dielectric layer positioned, in the direction orthogonal to the image plane, between the first conductive layer and the second conductive layer; and
a via configured to convey electrical current from the second conductive layer to the first conductive layer, wherein the via extends, in the direction orthogonal to the image plane, through the at least one dielectric layer.
10. The device of claim 8 , wherein the flexure comprises:
an inner frame fixedly coupled with the image sensor;
an outer frame fixedly coupled with the stationary structure of the camera;
one or more flexure arms that are connected to the inner frame and to the outer frame; and
electrical traces on at least a portion of the one or more flexure arms, wherein the electrical traces are configured to convey electrical signals between the inner frame and the outer frame.
11. The device of claim 10 , wherein at least one of the inner frame, the outer frame, or the one or more flexure arms comprise the plurality of layers stacked in the direction orthogonal to the image plane.
12. The device of claim 10 , wherein the actuator comprises a voice coil motor (VCM) actuator that includes:
a magnet; and
a coil positioned proximate the magnet, such that the coil is capable of electromagnetically interacting with the magnet to produce Lorentz forces that move the image sensor.
13. The device of claim 10 , wherein the actuator is configured to move the image sensor in at least one of:
the direction orthogonal to the image plane; or
directions parallel to the image plane.
14. The device of claim 8 , wherein:
the base layer has a thickness ranging from 30 microns to 150 microns; and
the conductive layer is a copper layer having a thickness ranging from 2 microns to 30 microns.
15. A camera, comprising:
a lens group;
an image sensor at an image plane;
an actuator to move the image sensor relative to the lens group; and
a flexure that suspends the image sensor from a stationary structure of the camera and that allows motion of the image sensor enabled by the actuator, the flexure comprising:
a plurality of layers stacked in a first direction, the plurality of layers comprising:
an electrical grounding portion, comprising a first conductive layer;
a signal trace interconnect portion, comprising:
an electrical signal pad for attaching the flexure with one or more other components; and
a second conductive layer defining an electrical signal trace;
wherein the electrical signal pad is positioned adjacent the electrical signal trace; and
an intermediate portion, comprising:
a dielectric layer positioned, in the direction orthogonal to the image plane, between the electrical grounding portion and the signal trace interconnect portion;
wherein a portion of the electrical grounding portion defines an impedance adjusting feature comprising (i) a void or (ii) a cavity that is at least partially filled with an insulating material, and wherein the impedance adjusting feature is positioned along an axis that intersects with the signal trace interconnect portion.
16. The camera of claim 15 , wherein:
the intermediate portion further comprises:
an adhesion layer adjacent the first conductive layer and the dielectric layer; and
the impedance adjusting feature is configured to increase the impedance of the electrical signal pad to a target impedance that is closer to the impedance of the electrical signal trace, relative to an impedance of the electrical signal pad if the flexure did not include the impedance adjusting feature.
17. The camera of claim 15 , wherein the impedance adjusting feature is an empty void.
18. The camera of claim 15 , wherein the impedance adjusting feature is an epoxy-filled cavity.
19. The camera of claim 15 , wherein the first conductive layer comprises:
a base layer comprising a metal alloy.
20. The camera of claim 15 , wherein the electrical grounding portion further comprises:
a base layer comprising a metal alloy;
wherein the first conductive layer is adjacent the base layer, and wherein the conductive layer provides a ground plane that reduces ground current resistance of the flexure, relative to a ground current resistance of the base layer without the conductive layer.