Camera module with electrostatic discharge protection
The present document describes a camera module with electrostatic discharge (ESD) protection. In particular, the camera module includes a lightning rod structure, which guides an ESD current to a safe location (e.g., system ground) when a lens retainer of the camera module is hit by an ESD spark. Due to the impact on camera focus tuning and the risk of audio rub and buzz, the lightning rod structure does not physically touch the lens retainer. As such, a gap separates the lightning rod structure from the lens retainer. When the lens retainer is stressed by an ESD spark, the gap is broken down and a conductive path is established to guide the ESD current to the safe location through the lightning rod structure. In this way, the ESD current flows along a controlled path instead of jumping to arbitrary locations, which protects nearby susceptible circuitry.
1. A camera module for an electronic device, the camera module comprising:
a camera lens;
an image sensor aligned with the camera lens;
a retainer encircling the camera lens, the retainer being movable during a focus tuning of the camera module; and
an electrostatic discharge bridge component arranged to provide a controlled path for an electrostatic discharge current to travel from the retainer to a system ground of the electronic device, the electrostatic discharge bridge component separated from the retainer by a gap and positioned to guide the electrostatic discharge current away from the image sensor.
2. The camera module of claim 1 , wherein the electrostatic discharge bridge component is configured to prevent the electrostatic discharge current from jumping to circuitry that is sensitive to the electrostatic discharge current.
3. The camera module of claim 2 , wherein the circuitry includes at least one of:
a camera board having the image sensor; or
a printed circuit board having one or more infrared light sources.
4. The camera module of claim 1 , wherein the gap separates the electrostatic discharge bridge component from the retainer by a width that is within a range of 0.5 millimeters to 5 millimeters.
5. The camera module of claim 1 , wherein the retainer is movable in a direction of an axial center of the camera lens.
6. The camera module of claim 1 , wherein the retainer is configured to receive the electrostatic discharge current from an electrostatic discharge spark jumping from an electrostatically charged person or object that touches or moves into proximity of the retainer.
7. The camera module of claim 1 , further comprising a lens holder configured to be mounted to a camera board having the image sensor and support the camera lens, wherein the electrostatic discharge bridge component is disposed on the lens holder.
8. The camera module of claim 7 , wherein the electrostatic discharge bridge component includes a planar shape and is oriented to have a plane defined by the planar shape be non-parallel to an axial center of the camera lens.
9. An electronic device comprising:
a housing;
circuitry that is sensitive to electrostatic discharge current;
a system ground for grounding the electrostatic discharge current; and
a camera module comprising:
a camera lens;
an image sensor aligned with the camera lens;
a retainer encircling the camera lens, the retainer being movable during a focus tuning of the camera module; and
an electrostatic discharge bridge component arranged to provide a controlled path for the electrostatic discharge current to travel from the retainer to the system ground, the electrostatic discharge bridge component separated from the retainer by a gap and positioned to guide the electrostatic discharge current away from the image sensor.
10. The electronic device of claim 9 , wherein the retainer is configured to extend outwardly from the housing and be exposed to an environment surrounding the electronic device.
11. The electronic device of claim 9 , wherein the retainer has a substantially tubular shape.
12. The electronic device of claim 9 , wherein the system ground includes a heat sink.
13. The electronic device of claim 12 , wherein:
the gap is a first gap;
the electrostatic discharge bridge component is separated from the heat sink by a second gap; and
the second gap separates the electrostatic discharge bridge component from the heat sink by a width that is within a range of 0.5 millimeters to 5 millimeters.
14. The electronic device of claim 9 , further comprising a printed circuit board disposed in proximity to the retainer, wherein the electrostatic discharge bridge component prevents the electrostatic discharge current from jumping to the printed circuit board.
15. The electronic device of claim 9 , wherein the electronic device is a video-recording doorbell.
16. The electronic device of claim 9 , wherein the retainer is movable in a direction of an axial center of the camera lens.
17. The electronic device of claim 9 , wherein the retainer is configured to receive the electrostatic discharge current from an electrostatic discharge spark jumping from an electrostatically charged person or object that touches or moves into proximity of the retainer.
18. The electronic device of claim 9 , wherein the circuitry includes a camera board having the image sensor.
19. The electronic device of claim 18 , further comprising a lens holder configured to be mounted to the camera board and support the camera lens, wherein the electrostatic discharge bridge component is disposed on the lens holder.
20. The electronic device of claim 19 , wherein the electrostatic discharge bridge component includes a planar shape and is oriented to have a plane defined by the planar shape be non-parallel to an axial center of the camera lens.