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EP-4381459-B1 - MULTI-CHANNEL HIGH-RESOLUTION IMAGING DEVICES INCORPORATING METALENSES

EP4381459B1EP 4381459 B1EP4381459 B1EP 4381459B1EP-4381459-B1

Inventors

  • QUAADE, ULRICH
  • MATTINSON, FREDRIK
  • FRANCOIS, OLIVIER
  • EILERTSEN, James
  • JOHANSEN, Villads Egede

Dates

Publication Date
20260506
Application Date
20220801

Claims (15)

  1. An apparatus (100) comprising: at least one image sensor (104) including a plurality of pixel arrays (102A, 102B), each of the pixel arrays being operable to acquire an image of a scene from a viewpoint that differs slightly from that of any other pixel array of the plurality of pixel arrays, each of the pixel arrays being part of a different one of a plurality of optical channels (106A, 106B), each of the optical channels configured for detection of incoming light rays of substantially a same particular wavelength or substantially a same particular range of wavelengths centered on substantially the same particular wavelength; a plurality of metalenses (108A, 108B), each of which is disposed, respectively, in a different one of the plurality of optical channels (106A, 106B) and is configured, respectively, to focus incoming light rays onto a different one of the pixel arrays; and readout and processing circuitry (114) operable to read out signals from the plurality of pixel arrays and to generate a respective lower-resolution monochromatic image for each of the optical channels corresponding to substantially the same particular wavelength or substantially the same particular range of wavelengths centered on substantially the same particular wavelength, and to process the lower-resolution monochromatic images to obtain a higher-resolution monochromatic image.
  2. The apparatus of claim 1 wherein each of the plurality of metalenses is configured to focus incoming light rays of the substantially same particular wavelength, or falling within the substantially same particular range of wavelengths, onto a respective one of the pixel arrays.
  3. The apparatus of claim 1 wherein each of the plurality of optical channels includes a respective optical filter.
  4. The apparatus of claim 3 wherein each optical filter is configured to pass light having the substantially same particular wavelength or falling within the substantially same particular range of wavelengths.
  5. The apparatus of any one of claims 3 or 4 wherein each of the optical filters is disposed between the image sensor and a different respective one of the metalenses.
  6. The apparatus of any one of claims 3 or 4 wherein each of the optical filters is disposed over a different respective one of the metalenses.
  7. The apparatus of any one of claims 1-6 wherein each of the pixel arrays is operable to acquire an image of a scene, and wherein there is a sub-pixel shift in the image acquired by a first one of the pixel arrays relative to the image acquired by a second one of the pixel arrays.
  8. The apparatus of any one of claims 1-7 wherein the at least one image sensor includes a plurality of image sensors, each of which includes a different respective one of the pixel arrays.
  9. The apparatus of any one of claims 1-7 wherein the at least one image sensor is a single image sensor that includes each of the pixel arrays.
  10. The apparatus of any one of claims 1-9 wherein the readout and processing circuitry is operable to process the lower-resolution images to obtain a higher-resolution monochromatic image using a super-resolution protocol.
  11. A method comprising: acquiring (200), by each of two or more pixel arrays being part of different respective optical channels of an imaging device, each of the pixel arrays being operable to acquire an image of a scene from a viewpoint that differs slightly from that of any other pixel array of the two or more pixel arrays, a respective lower-resolution monochromatic image of a scene, where each of the lower-resolution images is based on light rays passing through a respective metalens in a respective one of the optical channels, wherein each of the optical channels is configured for detection of light rays of substantially a same particular wavelength or substantially a same particular range of wavelengths centered on substantially the same particular wavelength; reading out (202), from the pixel arrays, signals representing the acquired lower-resolution images; and using (204) a super-resolution protocol to obtain a higher-resolution monochromatic image of the scene based on the lower-resolution monochromatic images.
  12. The method of claim 11 including displaying the higher-resolution image on a display screen of a computing device.
  13. The method of claim 11 including displaying the higher-resolution image on a display screen of a smartphone.
  14. The method of any one of claims 11-13 wherein each respective one of the plurality of metalenses focuses incoming light rays of the substantially same particular wavelength, or falling within the substantially same particular range of wavelengths centered on the particular wavelength, onto the respective one of the pixel arrays, optionally wherein each of the metalenses comprises meta-atoms arranged to resonate at a fixed frequency corresponding to the substantially same particular wavelength.
  15. The method of any one of claims 11-14 wherein there is a sub-pixel shift in the lower-resolution image acquired by a first one of the pixel arrays relative to the lower-resolution image acquired by a second one of the pixel arrays.

Description

FIELD OF THE DISCLOSURE The present disclosure relates to multi-channel imaging devices. BACKGROUND Multi-channel imaging devices can acquire images using image sensors. For example, light entering through an aperture at one end of an image device is directed to one or more image sensors, which include pixels that generate signals in response to sensing received light. The imaging devices sometimes are incorporated into handheld or other portable electronic devices such as smartphones. However, space in such portable devices often is at a premium. Thus, reducing the size or dimensions of the imaging device can be important for such applications. US 2011/080487 A1 discloses a imaging device capable of super-resolution processing using diffractive optics for achieving a compact size. US 2020/388642 A1 discloses usage of metalenses for compact imaging devices. SUMMARY The present disclosure describes multi-channel high-resolution imaging devices incorporating metalenses. In one aspect, for example, the present disclosure describes an apparatus according to claim 1. The present disclosure also describes a method according to claim 11. The details of one or more implementations are set forth in the accompanying drawings and the description below. Other aspects, features and advantages will be apparent from the following detailed description, the accompanying drawings, and the claims. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates a first example of an imaging device.FIG. 2 illustrates a second example of an imaging device.FIG. 3 illustrates a third example of an imaging device.FIG. 4 illustrates a fourth example of an imaging device.FIG. 5 is a flow chart of an example method for operation of the imaging devices of FIGS. 1 through 4. DETAILED DESCRIPTION As illustrated in the example of FIG. 1, a multi-channel imaging device 100 is operable to capture images by respective pixel arrays 102A, 102B that are associated with different channels and are part of one or more image sensors. In the illustrated example, a single image sensor 104 is shown and includes both pixel arrays 102A, 102B. In some implementations, each pixel array 102A, 102B is part of a different respective small image sensor, rather than a single larger image sensor. In any event, each image sensor can be implemented, for example, as a relatively low-cost, low-resolution CCD (charge-coupled device) image sensor or CMOS (complementary metal-oxide-semiconductor) image sensor. That is, although more expensive, high-resolution image sensors can be employed, it is not necessary to do so. Further, although the example of FIG. 1 shows only two optical channels 106A, 106B, some implementations may include a greater number of optical channels. Each optical channel is configured for detection of incoming light rays of a particular wavelength or a particular range of wavelengths centered on the particular wavelength. For each channel 106A, 106B, a respective metalens is provided to focus incoming light rays onto a respective one of the pixel arrays 102A, 102B. That is, a first metalens 108A, is disposed over the first part of the image sensor 104 that includes the first pixel array 102A, and a second metalens 108B, is disposed over the second part of the image sensor 104 that includes the second pixel array 102B. The first metalens 108A is configured to focus incoming light rays onto the first pixel array 102A, and the second metalens 108B is configured to focus incoming light rays onto the second pixel array 102B. Each metalens 108A, 108B has a metasurface, which refers to a surface with distributed small structures (e.g., meta-atoms) arranged to interact with light in a particular manner. For example, a metasurface, which also may be referred to as a metastructure, can be a surface with a distributed array of nanostructures. The nanostructures are configured to interact, individually or collectively, with light waves so as to change a local amplitude, a local phase, or both, of an incoming light wave. The meta-atoms (e.g., nanostructures) can be arranged to act as a metalens that resonates at a fixed frequency with a relatively sharp bandwidth. That is, the dimensions (e.g., diameter and length), shape, and material of the meta-atoms can be designed to induce a phase delay in an incident wave of a particular wavelength so as to focus an incident wave on a particular spot. In some implementations, the metalenses 108A, 108B are configured for a particular wavelength or narrow band of wavelengths in the infrared part of the electromagnetic spectrum, whereas in other implementations, the metalenses are configured for a particular wavelength or narrow band of wavelengths in another part of the spectrum (e.g., visible). In any event, each of the metalenses can be configured to focus, onto the respective pixel arrays, incoming light rays of a particular wavelength, or falling within a particular (e.g., narrow) range of wavelengths centered on the particular