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EP-4449182-B1 - LARGE-APERTURE COMPACT SCANNING TELE CAMERAS

EP4449182B1EP 4449182 B1EP4449182 B1EP 4449182B1EP-4449182-B1

Inventors

  • GOLDENBERG, EPHRAIM
  • Kowal, Yiftah
  • SHABTAY, GAL
  • BORAL, Itamar
  • SHEMESH, Ziv

Dates

Publication Date
20260506
Application Date
20221108

Claims (15)

  1. A scanning Tele camera (200, 250, 1250), STC, comprising: an optical path folding element, OPFE, for folding a first optical path (112), OP1, to a second optical path (108), OP2, wherein the OPFE has an OPFE height H O measured along OP1, an OPFE length L O measured along an axis parallel to OP2, an OPFE light entering surface and an OPFE light exiting surface; an OPFE actuator; a lens having a lens optical axis parallel to OP2, an effective focal length EFL, a f number f/#, a maximum lens aperture height H A measured along OP1, and a maximum lens aperture width W A measured along an axis perpendicular to both OP1 and OP2; and an image sensor having an image sensor diagonal SD and an image sensor height H Sensor measured along OP1; characterized in that the OPFE actuator is configured to rotate the OPFE around a first rotation axis perpendicular to both OP1 and OP2 and around a second rotation axis parallel to OP1 for scanning a scene with a native field-of-view, n-FOV T , wherein the first rotation axis is located at a distance Δ1 from the light exiting surface of the OPFE, and wherein Δ1/L O < 0.25.
  2. The STC according to claim 1, wherein Δ1/L O < 0.2.
  3. The STC according to claim 1 wherein the OPFE has an OPFE center with respect to OP1, wherein the first rotation axis is located at a distance Δ C from the OPFE center along OP1, and wherein a ratio of Δ C and H O fulfils Δ C /H O > 0.015.
  4. The STC according to claim 1, included in a camera module, wherein the camera module is divided into a module region having a module region height H M and a shoulder region having a shoulder region height H S < H M , all heights being measured along OP1, and wherein H S < H A + 3mm.
  5. The STC according to claim 4, wherein the OPFE is included in the module region and wherein the lens and the image sensor are included in the shoulder region.
  6. The STC according to claim 4, included in a mobile device, wherein the mobile device has a regular region with a regular thickness T and a bump region with a bump thickness T+B, wherein the shoulder region is included in the mobile device regular region and wherein the module region is included in the mobile device bump region.
  7. The STC according to claim 6, wherein the mobile device includes a Wide camera having a Wide camera image sensor and a Wide camera field-of-view (FOV W ), and wherein the scanning provides an effective Tele scanning FOV s-FOV T , wherein FOV W is in the range of 70-90 degrees, and wherein s-FOV T covers a 16:9 segment of FOV W .
  8. The STC according to claim 1, wherein SD/EFL > 0.4mm.
  9. The STC according to claim 1, wherein the scanning provides an effective Tele scanning FOV s-FOV T , wherein the s-FOV T has a longer horizontal side and a shorter vertical side, and wherein a horizontal side H-FOV T of s-FOV T is greater than 40 degrees.
  10. The STC according to claim 1, wherein the rotation of the OPFE along the first rotation axis is by more than ±5 degrees around a zero scan position.
  11. The STC according to claim 1, wherein EFL =10-25mm.
  12. The STC according to claim 1, wherein f/# < 3.5.
  13. A mobile device comprising the STC according to claim 1, wherein the mobile device further comprises an application processor (AP).
  14. The mobile device according to claim 13, wherein the mobile device further comprises a Wide camera, wherein the AP is configured to use image data from the Wide camera for autonomous scanning of a scene with the STC's n-FOV T .
  15. The mobile device according to claim 13, wherein the AP is configured to scan a scene with the STC's n-FOV T according to a user input.

Description

FIELD The subject matter disclosed herein relates in general to compact mobile cameras and in particular to mobile scanning telephoto ("Tele") cameras. DEFINITIONS In this application and for optical and other properties mentioned throughout the description and figures, the following symbols and abbreviations are used, all for terms known in the art: Lens element: a single lens element.Lens: assembly of a plurality of lens elements.Total track length (TTL): the maximal distance, measured along an axis parallel to the optical axis of a lens, between a point of the front surface S1 of a first lens element L1 and an image sensor, when the system is focused to an infinity object distance.Back focal length (BFL): the minimal distance, measured along an axis parallel to the optical axis of a lens, between a point of the rear surface S2N of the last lens element LN and an image sensor, when the system is focused to an infinity object distance.Effective focal length (EFL): in a lens (assembly of lens elements L1 to LN), the distance between a rear principal point P' and a rear focal point F' of the lens.f-number (f/#): the ratio of the EFL to an entrance pupil (or aperture) diameter of a lens. BACKGROUND Mobile electronic handheld devices (or just "mobile devices") such as smartphones having two or more compact cameras (also referred to as "multi-cameras") are known. The two or more cameras have lenses with different effective focal lengths (EFLs) that capture images of a same scene with different fields of view (FOVs). For example, a multi-camera may include a Wide camera having a Wide camera FOV ("FOVW") of e.g. 80 degrees and a Tele (or "zoom") camera having a narrower FOV ("native FOVT" or "n-FOVT") of e.g. 25 degrees and with higher spatial resolution (for example 3-5 times higher) than that of the Wide camera. Tele cameras with scanning capability ("scanning Tele cameras" or "STCs") for expanding the native fields-of-view n-FOVT to an effective Tele FOV (also referred to as "scanning FOVT" or "s-FOVT") overcome some of the limitations that relate to narrow n-FOVTs. Compact STCs can be realized in a folded camera such as described for example in co-owned US patent 10578948, or in a double-folded camera such as described for example in co-owned international patent PCT/IB2021/059843. One or two optical path folding elements (OPFEs), for example prisms or mirrors, are rotated along one or two directions to direct (or "scan" or "steer") the n-FOVT towards arbitrary points of view (POVs) within s-FOVT. The f-number ("f/#") of a camera lens is the ratio of the EFL to the aperture diameter ("DA"): f/# = EFL/DA. As known in the art, a low f/# is desired as of 3 major advantages: High signal-to-noise ratio (SNR), strong "natural" Bokeh effect and support of high image resolutions. A low f/# is, amongst others, achieved by maximizing the aperture area of the camera lens. It is noted that herein, "aperture" refers to an entrance pupil of a lens (or "lens assembly"). If it is referred to an "aperture of a camera" or an "aperture of an optical lens system", this always refers to the aperture of the lens included in the camera or in the optical lens system respectively. "Aperture" and "clear aperture" are used interchangeably. US Patent Application Publication US 2019/0394396 A1, titled CAMERA WITH PANORAMIC SCANNING RANGE, appears to describe cameras with panoramic scanning range comprising a folded digital camera in which an optical path folding element (OPFE) that folds a first optical path from an object or scene into a second optical path substantially parallel with an optical axis of a lens of the folded camera, the OPFE being rotatable around the lens optical axis, and systems incorporating such cameras. There is need and it would be beneficial to have a compact scanning Tele camera for incorporation in a mobile device that includes a lens having a large aperture area and low f number. SUMMARY In various exemplary embodiments (examples), there is provided a scanning Tele cameras (STC) comprising: an OPFE for folding a first optical path OP1 to a second optical path OP2, wherein the OPFE has an OPFE height HO measured along OP1, an OPFE length LO measured along an axis parallel to OP, and a light exiting surface; an OPFE actuator; a lens having a lens optical axis parallel to OP2, an EFL, a maximum lens aperture height HA measured along OP1, and a maximum lens aperture width WA measured along an axis perpendicular to both OP1 and OP2; and an image sensor having an image sensor diagonal (SD) and an image sensor height HSensor measured along OP1, wherein the STC has a STC native field-of-view (n-FOVT), wherein the OPFE actuator is configured to rotate the OPFE around a first rotation axis perpendicular to both OP1 and OP2 and around a second rotation axis parallel to OP1 for scanning a scene with the n-FOVT, wherein the first rotation axis is located at a distance Δ1 from the light exiting surface of the OPFE, and wher