FIELD

This application is generally related to image sensor, and more specifically to techniques for extending field of view (FOV) of image sensor.

BACKGROUND

An image sensor can detect and convey information used to make an image. The image sensor can capture light reflected from a scene and convert the captured light into signals. The light can include, for example, visible light, infra-red light, etc. The signals can be used to generate an image of the scene to support various applications, such as depth-sensing, location tracking, augmented reality (AR)/virtual reality (VR)/mixed reality (MR) applications, etc.

One important performance metric of an imaging system is an extent of a scene that can be imaged by the image sensor. The extent can be affected by various parameters, such as a field of view (FOV) of the image sensor, which measures an angular extent of the scene that can be imaged by the image sensor. FOV can be used interchangeably with angle of view (AOV). It is desirable that an image sensor has a wide FOV, such that the image sensor can image a larger area of a scene and can capture more information about the scene in an image.

SUMMARY

Techniques are described for improving a field of view of an image sensor. The techniques can also be used to improve a field of illumination of an illuminator.

In some embodiments, an apparatus comprises: one or more covers having at least a first opening and a second opening; a first lens mounted in the first opening and having a first field of view (FOV) centered at a first axis having a first orientation; a second lens mounted in the second opening and having a second FOV centered at a second axis having a second orientation different from the first orientation; a first image sensor housed within the one or more covers and configured to detect light via the first lens; and a second image sensor housed within the one or more covers and configured to detect light via the second lens. The first image sensor and the second image sensor are configured to provide, based on the detected light, image data of a combined FOV larger than each of the first FOV and the second FOV.

In some aspects, the apparatus further comprises a support structure having a first surface perpendicular to the first axis and a second surface perpendicular to the second axis. The first image sensor is formed on the first surface. The second image sensor is formed on the second surface.

In some aspects, the apparatus further comprises a first circuit board on which the first image sensor and the second image sensor are formed. The first circuit board is bonded with the first surface and the second surface of the support structure.

In some aspects, the first circuit board is bonded with the first surface and the second surface of the support structure with an epoxy material.

In some aspects, the apparatus further comprises a second circuit board. Two ends of the first circuit board are bonded with the second circuit board such that the support structure is sandwiched between the first circuit board and the second circuit board.

In some aspects, the two ends of the first circuit board comprise first pads. The second circuit board comprises second pads. The first pads at the two ends of the first circuit board are soldered to the second pads of the second circuit board.

In some aspects, each of the first circuit board and the second circuit board includes a rigid-flex circuit board.

In some aspects, the apparatus further comprises a processor bonded with the second circuit board and electrically connected to the first image sensor and the second image sensor. The processor is configured to: receive a first image frame from the first mage sensor corresponding to the first FOV; receive a second image frame from the second image sensor corresponding to the second FOV; and generate a combined image frame corresponding to the combined FOV based on the first image frame and the second image frame.

In some aspects, the processor is configured to generate the combined image frame based on identifying pixels of an object captured in both the first image frame and the second image frame.

In some aspects, the processor is sandwiched between the support structure and the second circuit board.

In some aspects, the processor is electrically connected to the second circuit board via at least one of: flip chip connectors, or bond wires.

In some aspects, the one or more covers include one cover mounted on the second circuit board.

In some aspects, the one or more covers include a first cover having the first opening and a second cover having the second opening. The first cover is formed on the first surface of the support structure. The second cover is formed on the second surface of the support structure.

In some aspects, the apparatus further comprises a third cover having a transparent lid. The third cover is formed on the second circuit board. The transparent lid allows light to reach the first lens and the second lens.

In some aspects, the apparatus further comprises an illuminator configured to emit the light.

In some embodiments, a method of fabricating an image sensor module is provided. The method comprises: forming electrical connections between a processor and a first circuit board; bonding a support structure onto a surface of the processor; placing a first image sensor and a second image sensor on a second circuit board; bonding the second circuit board comprising the first and second image sensors on a first surface and a second surface of the support structure, the first surface and the second surface having different orientations; forming electrical connections between the first circuit board and the second circuit board bonded to the support structure; and placing a cover having a first lens and a second lens on the first circuit board to enclose the first and second image sensors, the first lens having a first field of view (FOV) centered at a first axis perpendicular to the first surface and the second lens having a second FOV centered at a second axis perpendicular to the second surface.

In some aspects, the electrical connections between the processor and the first circuit board comprise at least one of: flip-chip connections, or bond wires. The electrical connections between the first circuit board and the second circuit board comprise at least one of: flip-chip connections, or bond wires.

In some aspects, support structure is bonded onto the surface of the processor based on an epoxy material. Forming electrically connections between the first circuit board and the second circuit board bonded to the support structure comprises using a hot bar to simultaneously solder first pads on two ends of the second circuit board onto second pads on the first circuit board.

In some aspects, each of the first circuit board and the second circuit board include a rigid-flex circuit board.

