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EP-4602428-B1 - COMPACT FOLDED TELE CAMERAS WITH SLIM HIGH IMAGE QUALITY OPTICAL IMAGE STABILIZATION ACTUATOR

EP4602428B1EP 4602428 B1EP4602428 B1EP 4602428B1EP-4602428-B1

Inventors

  • GOLDSTEIN, KOBI
  • GOLDENBERG, EPHRAIM
  • WEITZ, Tom

Dates

Publication Date
20260513
Application Date
20241106

Claims (15)

  1. A folded camera, comprising: a lens that includes a plurality of lens elements L i divided into a first lens group (G1) and into a second lens group (G2) and having an effective focal length (EFL) in the range of 8mm<EFL<40mm; an image sensor; an optical path folding element (OPFE) for folding a first optical path (OP1) to a second optical path (OP2), wherein G1 is located at an object side of the OPFE and wherein G2 is located at an image side of the OPFE, and wherein the OPFE has a height H O measured along OP1; and an optical image stabilization (OIS) actuator operational to perform OIS and including a single motor, wherein the folded camera is a folded Tele camera, wherein the single motor is operational to perform OIS along a first OIS direction by jointly rotating G1 around a G1 rotation axis by a G1 rotational stroke (Rot G1 ) and rotating the OPFE around an OPFE rotation axis by an OPFE rotational stroke (Rot OPFE ) < Rot G1 , wherein the G1 rotation axis and the OPFE rotation axis are parallel to each other and perpendicular to both OP1 and OP2, and characterised in that a distance d ROT between the G1 rotation axis and the OPFE rotation axis fulfills 2.5 < H O /d ROT < 7.5.
  2. The folded camera of claim 1, wherein 3 < H O /d ROT < 6.
  3. The folded camera of claim 1, wherein the OIS actuator comprises a lever system that includes at least a first lever, a second lever, and a lever reference point, and wherein the first lever and the second lever define respective positions of the G1 rotation axis and of the OPFE rotation axis.
  4. The folded camera of claim 3, wherein a straight line connecting the OPFE rotation axis and the lever reference point forms an angle α with OP1, wherein a straight line connecting the G1 rotation axis and the lever reference point forms an angle β with OP1, wherein a straight line connecting the G1 rotation axis and the lever reference point forms an angle γ with OP2, and wherein 60deg < α < 120deg, 30deg < β < 90deg and 0deg < γ < 90deg.
  5. The folded camera of claim 4, wherein the first lever is a G1 lever fixedly coupled to G1 and having a length L G1 , wherein the second lever is an OPFE lever fixedly coupled to the OPFE and having a length L OPFE , wherein a lever ratio L G1 :L OPFE and angles α, β and γ define a rotational stroke ratio Rot OPFE :Rot G1 in the range of 1:1.25 to 1:3, and wherein L G1 :L OPFE is in the range 0.5:1 to 1:2.
  6. The folded camera of claim 5, wherein L G1 :L OPFE is in the range 0.75:1 to 0.95:1.
  7. The folded camera of claim 5, wherein L G1 is in the range of 2mm - 5mm.
  8. The folded camera of claim 5, wherein Rot OPFE :Rot G1 is in the range of 1:1.4 to 1:8.
  9. The folded camera of claim 3, wherein the lever reference point is a rolling hinge.
  10. The folded camera of claim 3, wherein the OIS actuator includes two ball-bearings that define the G1 rotation axis, two ball-bearings that define the OPFE rotation axis and one ball-bearing that defines the lever reference point.
  11. The folded camera of any of the preceding claims, wherein the single motor is a voice coil motor (VCM) that includes two or more coils and two or more magnets.
  12. The folded camera of any of the preceding claims, wherein the folded camera includes three or more preload springs, and wherein a first preload spring is located at a first side of the OPFE, and wherein a second preload spring and a third preload spring are located at second side of the OPFE
  13. The folded camera of any of the preceding claims, wherein the single motor is operational to rotate G1 and the OPFE together around an axis parallel to OP2 to perform OIS along a second OIS direction.
  14. The folded camera of any of the preceding claims, wherein the OPFE is a prism.
  15. The folded camera of any of the claims 1-14, wherein the folded camera is included in a smartphone.

Description

CROSS REFERENCE TO RELATED APPLICATIONS This application claims the benefit of priority from U.S. provisional patent applications No. 63,597,017 filed November 8, 2023. FIELD The presently disclosed subject matter is generally related to the field of digital 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: 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 that faces an object 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 diameter (or simply aperture diameter "DA"), f/# = EFL/DA. BACKGROUND Multi-aperture cameras (or "multi-cameras", of which a "dual-cameras" having two cameras is an example) are today's standard for portable electronic mobile devices ("mobile devices", e.g. smartphones, tablets, headsets, smartwatches etc.). A multi-camera usually comprises a wide field-of-view (or "angle") FOVW camera ("Wide" camera or "W" camera), and at least one additional camera, e.g. with a narrower (than FOVW) FOV (Telephoto or "Tele" camera with FOVT. FIG. 1A shows schematically an embodiment of a known folded Tele camera 100. For simplicity, such a camera may be referred to herein simply as "folded camera", with the understanding that all such folded cameras are "Tele" cameras. Camera 100 comprises a lens 102, an optical path folding element (OPFE) 104, e.g. a prism or a mirror, and an image sensor 106 having a sensor height HS. Here and in the following, a height is measured along OP1. OPFE 104 folds a first optical path ("OP1") 108 to a second optical path (OP2) 110. Lens 102 includes a plurality of N lens elements (here: N=7) numbered L1 - L7, which is divided in two lens groups, a first group 102-G1 ("G1") that includes L1 - L4 and has a thickness TG1, is located at an object side of the OPFE and has a lens optical axis which is parallel to OP1, and a second lens group 102-G2 ("G2") that includes L5-L7 and has a thickness TG2, is located at an image side of the OPFE and has a lens optical axis which is parallel to OP2, i.e. normal to sensor 106. Lens elements included in any of G1 or G2 respectively do not move relative to each other. Lens 102 has a lens width WL (measured along OP2). Here and in the following, a width is measured along an axis perpendicular to OP1. A distance between 102-G1 and OPFE 104 is marked ΔLO. A width of OPFE 104 is marked WOPFE. A TTL of camera 100 is divided into TTL1 and TTL2. TTL1 is parallel to OP1 108, TTL2 is parallel to OP2 110 and TTL=TTL1+TTL2. An aperture of camera 100 is numbered 112. A theoretical limit for a length of a camera module ("minimum module length" or "MLM"), a first height of a camera module in a "module" region ("minimum module height" or "MHM"), and a second height of a camera module in a "shoulder" region ("minimum shoulder height" or "MHS"), wherein MHM > MHS, including camera 100 is shown. MLM, MHM and MHS are defined by the smallest dimensions of the components included in camera 100. Hereinafter "HM" denotes "camera module height", or simpler just "module height", and "HS" denotes "camera shoulder height", or simpler just "shoulder height". The camera module includes a housing 114. FIG. 1B shows schematically a mobile device 120 (e.g. a smartphone) including known folded camera 100 in a cross-sectional view. Aperture 112 of camera 100 is located at rear surface 122. A front surface 124 may e.g. include a screen (not shown). Mobile device 120 has a regular region 126 of thickness ("T") and a camera bump region 128 that is elevated by a height B over regular region 126. Bump region 128 has a bump length ("BL") and a bump thickness T+B. The module region of camera 100 may be integrated into bump region 128, and the shoulder region may be integrated into regular region 126, as shown. For industrial design reasons, a small camera bump (i.e. a short BL) is desired. Camera 100 is integrated in the bump region only partially, what allows a relatively short BL. In general and for slim mobile devices, it is beneficial to minimize MHM and MHS. Especially minimizing MHM is of interest, as it allows minimizing B. For a compact camera, minimizing MLM is also beneficial. Especially minimizing R1 is of interest, as it allows minimizing BL. FIG. 1C illustrates a known dual-camera 150 th