U.S. patent application number 17/013561 was filed with the patent office on 2021-10-28 for optical-path folding-element with an extended two degree of freedom rotation range.
The applicant listed for this patent is Corephotonics Ltd.. Invention is credited to Gil Bachar, Gal Barak, Ephraim Goldenberg, Yiftah Kowal, Itay Yedid.
Application Number | 20210333126 17/013561 |
Document ID | / |
Family ID | 1000005895392 |
Filed Date | 2021-10-28 |
United States Patent
Application |
20210333126 |
Kind Code |
A9 |
Yedid; Itay ; et
al. |
October 28, 2021 |
OPTICAL-PATH FOLDING-ELEMENT WITH AN EXTENDED TWO DEGREE OF FREEDOM
ROTATION RANGE
Abstract
Actuators for rotating an optical-path-folding-element with two,
first and second, degrees of freedom in an extended rotation range
around two respective rotation axes, folded cameras including such
actuators and dual-cameras including a folded camera as above
together with an upright camera.
Inventors: |
Yedid; Itay; (Karme Yosef,
IL) ; Goldenberg; Ephraim; (Ashdod, IL) ;
Bachar; Gil; (Tel Aviv, IL) ; Barak; Gal; (Tel
Aviv, IL) ; Kowal; Yiftah; (Rehovot, IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Corephotonics Ltd. |
Tel Aviv |
|
IL |
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Prior
Publication: |
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Document Identifier |
Publication Date |
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US 20200400464 A1 |
December 24, 2020 |
|
|
Family ID: |
1000005895392 |
Appl. No.: |
17/013561 |
Filed: |
September 5, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16615310 |
Nov 20, 2019 |
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PCT/IB2019/053315 |
Apr 22, 2019 |
|
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17013561 |
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62661158 |
Apr 23, 2018 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G01P 13/00 20130101;
G02B 13/0065 20130101; G01D 5/145 20130101; G02B 7/18 20130101;
H01F 7/02 20130101 |
International
Class: |
G01D 5/14 20060101
G01D005/14; G02B 13/00 20060101 G02B013/00; G02B 7/18 20060101
G02B007/18; H01F 7/02 20060101 H01F007/02; G01P 13/00 20060101
G01P013/00 |
Claims
1. A sensing mechanism for sensing rotation movement around a
rotation axis, comprising: a) a magnet; and b) a magnetic sensor
configured to detect a magnetic flux of the magnet and to determine
a relative shift between the magnet and the magnetic sensor based
on change in the detected magnetic flux, wherein the magnet is
shaped such that a cross section of the magnet has a width that
increases from a point substantially at a center of the magnet
towards each end of the magnet, thereby increasing a range of
detectable change in the magnetic flux and increasing a
corresponding detectable range of the relative shift between the
magnet and the magnetic sensor.
2. The sensing mechanism of claim 1, wherein the detectable range
of the relative shift between the magnet and the magnetic sensor is
of more than 0.8 mm.
3. The sensing mechanism of claim 1, wherein the detectable range
of relative shift between the magnet and the magnetic sensor is of
more than 1.0 mm.
4. The sensing mechanism of claim 1, wherein the detectable range
of relative shift between the magnet and the magnetic sensor is of
more than 2.0 mm.
5. The sensing mechanism of claim 1, wherein the magnetic sensor is
a Hall bar sensor.
6. The sensing mechanism of claim 2, wherein the magnetic sensor is
a Hall bar sensor.
7. The sensing mechanism of claim 3, wherein the magnetic sensor is
a Hall bar sensor.
8. The sensing mechanism of claim 4, wherein the magnetic sensor is
a Hall bar sensor.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation application from U.S.
patent application Ser. No. 16/615,310 filed Nov. 20, 2019, which
was a 371 application from international patent application
PCT/IB2019/053315 filed Apr. 22, 2018, and is related to and hereby
claims the priority benefit of commonly-owned and co-pending U.S.
Provisional Patent Application No. 62/661,158 filed Apr. 23, 2017,
which is incorporated herein by reference in its entirety.
FIELD
[0002] The subject matter disclosed herein relates in general to a
folded-lens and to digital cameras with one or more folded
lens.
BACKGROUND
[0003] In recent years, mobile devices such as cell-phones (and in
particular smart-phones), tablets and laptops have become
ubiquitous. Many of these devices include one or two compact
cameras including, for example, a main rear-facing camera (i.e. a
camera on the back face of the device, facing away from the user
and often used for casual photography), and a secondary
front-facing camera (i.e. a camera located on the front face of the
device and often used for video conferencing).
[0004] Although relatively compact in nature, the design of most of
these cameras is similar to the traditional structure of a digital
still camera, i.e. it comprises a lens module (or a train of
several optical elements) placed on top of an image sensor. The
lens module refracts the incoming light rays and bends them to
create an image of a scene on the sensor. The dimensions of these
cameras are largely determined by the size of the sensor and by the
height of the optics. These are usually tied together through the
focal length ("f") of the lens and its field of view (FOV)--a lens
that has to image a certain FOV on a sensor of a certain size has a
specific focal length. Keeping the FOV constant, the larger the
sensor dimensions (e.g. in a X-Y plane), the larger the focal
length and the optics height.
[0005] A "folded camera module" structure has been suggested to
reduce the height of a compact camera. In the folded camera module
structure, an optical path folding element (referred to hereinafter
as "OPFE" that includes a reflection surface such as a prism or a
mirror; otherwise referred to herein collectively as a "reflecting
element") is added in order to tilt the light propagation direction
from a first optical path (e.g. perpendicular to the smart-phone
back surface) to a second optical path, (e.g. parallel to the
smart-phone back surface). If the folded camera module is part of a
dual-aperture camera, this provides a folded optical path through
one lens module (e.g. a Tele lens). Such a camera is referred to
herein as a "folded-lens dual-aperture camera" or a "dual-aperture
camera with a folded lens". In some examples, the folded camera
module may be included in a multi-aperture camera, e.g. together
with two "non-folded" camera modules in a triple-aperture
camera.
[0006] A folded-lens dual-aperture camera (or "dual-camera") with
an auto-focus (AF) mechanism is disclosed in Applicant's US
published patent application No. 20160044247.
SUMMARY
[0007] According to one aspect of the presently disclosed subject
matter there is provided an actuator for rotating an OPFE in two
degrees of freedom in an extended rotation range a first
sub-assembly, a second sub-assembly and a stationary sub-assembly,
the first sub-assembly configured to rotate the OPFE relative to
the stationary sub-assembly in an extended rotation range around a
yaw rotation axis and the second sub-assembly configured to rotate
the OPFE relative to the first sub-assembly in an extended rotation
range around a pitch rotation axis that is substantially
perpendicular to the yaw rotation axis; a first sensor configured
to sense rotation around the yaw rotation axis and a second sensor
configured to sense rotation around the pitch rotation axis, the
first and second sensors being fixed to the stationary
sub-assembly, wherein at least one of the first sensor or the
second sensor is a magnetic flux sensor; and a voice coil motor
(VCM) comprising a magnet and a coil, wherein the magnet is fixedly
attached to one of the first sub-assembly or the second
sub-assembly, wherein the coil is fixedly attached to the
stationary sub-assembly, wherein a driving current in the coil
creates a force that is translated to a torque around a respective
rotation axis, and wherein the second sensor is positioned such
that sensing by the second sensor is decoupled from the rotation of
the OPFE around the yaw rotation axis.
[0008] In addition to the above features, the actuator according to
this aspect of the presently disclosed subject matter can
optionally comprise one or more of features (i) to (xxv) listed
below, in any technically possible combination or permutation:
[0009] i. wherein the actuator is adapted to be installed and
operable in a folded digital camera for rotating the OPFE within
the camera, [0010] ii. wherein the actuator comprises a first
actuation mechanism (including a first VCM) configured to rotate
the first sub-assembly around the yaw rotation axis and a second
actuation mechanism (including a second VCM) configured to rotate
the second sub-assembly around the yaw rotation axis, [0011] iii.
wherein the actuator comprises a first sensing mechanism that
comprises the first sensor and a respective first magnet configured
to sense the rotation around the yaw rotation axis and a second
sensing mechanism that comprises the second sensor and a second
magnet configured to sense the rotation around the pitch rotation
axis, [0012] iv. wherein the yaw rotation axis passes through the
second sensor to thereby decouple the second sensor from rotation
around the yaw axis, [0013] v. wherein the yaw rotation axis passes
through a center of the second sensor, [0014] vi. wherein the
actuator further comprises a first curved ball-guided mechanism
operative to enable the rotation around the pitch axis, and a
second curved ball-guided mechanism operative to enable the
rotation around the yaw axis, [0015] vii. wherein the actuator
further comprises a curved ball-guided mechanism operative to
enable the rotation around the yaw axis, the curved ball-guided
mechanism is located on a side of the OPFE which is opposite to
side facing an image sensor, [0016] viii. wherein the extended
rotation range is equal to or greater than .+-.5 degrees around the
pitch and yaw rotation axes, [0017] ix. wherein the extended
rotation range is equal to or greater than .+-.10 degrees the pitch
and yaw rotation axes, [0018] x. wherein the extended rotation
range is between .+-.15-40 degrees around the pitch and yaw
rotation axes, [0019] xi. wherein the extended rotation range
around the pitch rotation axis is different from the extended
rotation range around the second rotation axis, [0020] xii. wherein
the at least one voice coil motor includes a pitch magnet and a
coil dedicated for generating the rotation around the pitch
rotation axis and wherein the pitch magnet is designed with a flat
surface facing the coil, [0021] xiii. wherein the magnetic sensor
is a magnetic flux sensor such as a Hall sensor. [0022] xiv.
wherein the actuator comprises a sensing mechanism that includes
the first sensor and a magnet (e.g. yaw sensing magnet), the magnet
is shaped or formed such that a central part of the sensing magnet
is further away from a projection line of motion of the first
sensor, relative to an end of the sensing magnet, [0023] xv.
wherein the actuator comprises a sensing magnet (e.g. yaw sensing
magnet) shaped such that width of a cross section of the sensing
magnet increases from a point substantially at its center towards
each end of the magnet, thereby resulting in a variable distance
between the first sensor and the magnet when relative movement
occurs between the sensing magnet and the sensor, [0024] xvi.
wherein the actuator further comprises a first magnet-yoke pair
which pulls the first sub-assembly to the second sub-assembly in a
radial direction relative to the pitch rotation axis and a second
magnet-yoke pair which pulls the first sub-assembly to the
stationary sub-assembly in a radial direction relative to the yaw
rotation axis, [0025] xvii. wherein the first sub-assembly
comprises a middle moving frame, the second sub-assembly comprises
an OPFE holder, and the stationary sub-assembly comprises a base;
wherein the first magnet-yoke pair pulls the OPFE holder to middle
moving frame and the second magnet-yoke pair pulls the middle
moving frame to the base, [0026] xviii. wherein the first
sub-assembly comprises a middle moving frame and the second
sub-assembly comprises an OPFE holder, and the stationary
sub-assembly comprises a base; wherein rotation around the yaw
rotation axis is generated by rotating the middle moving frame
relative to the base and rotation around the pitch rotation axis is
generated by rotating the OPFE holder relative to the middle moving
frame, [0027] xix. wherein the actuator comprises a magnet
characterized by a cut sphere shape and a coil characterized by a
circular shape, the coil is symmetrically positioned around the cut
sphere, [0028] xx. wherein the actuator comprises a single magnet
that is used for creating an actuation force for rotation around
the yaw rotation axis, creating a pre-load force in a magnet-yoke
pair for holding together the first sub-assembly and the stationary
sub-assembly, and sensing the rotation around the yaw rotation
axis. [0029] xxi. wherein the actuator comprises only one magnetic
flux sensor that is used for sensing rotation around the yaw
rotation axis, [0030] xxii. wherein the single magnet is a
polarization magnet characterized by continuous changes in
direction of a magnetic field of the magnet along the magnet's
length. wherein the first and second sensing mechanisms are
decoupled from each other, [0031] xxiii. wherein the actuator is
designed to be installed in a folded camera that comprises a lens
module accommodating a plurality of lens elements along an optical
axis; wherein the OPFE redirects light that enters the folded
camera from a direction of a view section along a first optical
path to a second optical path that passed along the optical axis,
[0032] xxiv. wherein the actuator comprises a pitch magnet located
at a side of the OPFE that is opposite to the side facing the view
section, [0033] xxv. wherein the actuator comprises a yaw magnet
located at a side of the OPFE that is opposite to the side facing
the lens module,
[0034] According to another aspect of the presently disclosed
subject matter there is provided a folded camera comprising the
actuator according to the previous aspect.
[0035] In addition to the above features, the folded camera
according to this aspect of the presently disclosed subject matter
can optionally comprise one or more of features (i) to (xxv) listed
above, in any technically possible combination or permutation.
[0036] According to yet another aspect of the presently disclosed
subject matter there is provided an actuator for rotating an OPFE
with a first degree of freedom (DOF) around a first rotation axis
and a second DOF around a second rotation axis, comprising:
[0037] a) a first actuation mechanism for rotation in the first
DOF;
[0038] b) a first sensing mechanism for sensing movement in the
first DOF;
[0039] c) a second actuation mechanism for rotation in the second
DOF; and
[0040] d) a second sensing mechanism for sensing movement in the
second DOF;
[0041] wherein first and second actuation mechanisms are configured
to rotate the OPFE around the respective first or second rotation
axis in an extended rotation range,
[0042] and wherein in some examples the first and second actuation
mechanism are voice coil motors and the second sensing mechanism
comprises a sensor positioned such that rotation of the OPFE around
the first rotation axis is decoupled from the second sensor.
[0043] In addition to the above features, the camera according to
this aspect of the presently disclosed subject matter can
optionally comprise one or more of features (i) to (xxv) listed
above, in any technically possible combination or permutation.
[0044] According to another aspect of the presently disclosed
subject matter there is provided a sensing mechanism for sensing
rotation movement around a rotation axis, comprising a magnet and a
magnetic sensor configured to detect a magnetic flux of the magnet
and to determine a relative shift between the magnet and the
magnetic sensor based on change in the detected magnetic flux,
wherein the magnet is shaped such that a cross section of the
magnet has a width that increases from a point substantially at a
center of the magnet towards each end of the magnet, thereby
increasing a range of detectable change in the magnetic flux and
increasing a corresponding detectable range of the relative shift
between the magnet and the magnetic sensor.
[0045] In addition to the above features, the actuator according to
this aspect of the presently disclosed subject matter can
optionally comprise one or more of features (i) to (iv) listed
below, in any technically possible combination or permutation:
[0046] i. wherein the detectable range of relative shift between
the magnet and the magnetic sensor is of more than 0.8 mm, [0047]
ii. wherein the detectable range of relative shift between the
magnet and the magnetic sensor is of more than 1.0 mm, [0048] iii.
wherein the detectable range of relative shift between the magnet
and the magnetic sensor is of more than 2.0 mm, and [0049] iv.
wherein the magnetic sensor is a Hall bar sensor.
BRIEF DESCRIPTION OF THE DRAWINGS
[0050] Non-limiting examples of the presently disclosed subject
matter are described below with reference to figures attached
hereto that are listed following this paragraph. Identical
structures, elements or parts that appear in more than one figure
may be labeled with the same numeral in the figures in which they
appear. The drawings and descriptions are meant to illuminate and
clarify embodiments disclosed herein, and should not be considered
limiting in any way.
[0051] FIG. 1A illustrates a folded camera with an optical path
folding element (OPFE) with an extended 2 degrees-of-freedom (DOF)
rotation range, according to some examples of the presently
disclosed subject matter;
[0052] FIG. 1B shows the folded camera of FIG. 1A with an OPFE
actuator, according to some examples of the presently disclosed
subject matter;
[0053] FIG. 1C shows a dual-camera the includes a folded camera as
in FIG. 1A together with an upright (non-folded) camera, according
to according to some examples of the presently disclosed subject
matter;
[0054] FIG. 2A shows an OPFE actuator of the folded camera of FIG.
1 in an isometric view, according to some examples of the presently
disclosed subject matter;
[0055] FIG. 2B shows the actuator in FIG. 2A without a shield,
according to some examples of the presently disclosed subject
matter;
[0056] FIG. 3A shows a top actuated sub-assembly of the actuator of
FIGS. 2A and 2B from one side, according to some examples of the
presently disclosed subject matter;
[0057] FIG. 3B shows the top actuated sub-assembly of FIG. 3A from
an opposite side, according to some examples of the presently
disclosed subject matter;
[0058] FIG. 3C shows the top actuated sub-assembly of FIG. 3A in an
exploded view, according to some examples of the presently
disclosed subject matter;
[0059] FIG. 4A shows a bottom actuated sub-assembly of the actuator
of FIGS. 2A and 2B from one side, according to some examples of the
presently disclosed subject matter;
[0060] FIG. 4B shows the bottom actuated sub-assembly of FIG. 4A
from an opposite side, according to some examples of the presently
disclosed subject matter;
[0061] FIG. 4C shows the bottom actuated sub-assembly in an
exploded view, according to some examples of the presently
disclosed subject matter;
[0062] FIG. 5A shows the top and bottom actuated sub-assemblies
installed together in an isometric view, according some examples of
the presently disclosed subject matter;
[0063] FIG. 5B shows the top and bottom actuated sub-assemblies
installed together in a cut along a line A-B shown in FIG. 5A,
according to some examples of the presently disclosed subject
matter;
[0064] FIG. 6A shows a stationary sub-assembly of the actuator of
FIGS. 2A and 2B from one side, according to some examples of the
presently disclosed subject matter;
[0065] FIG. 6B shows the stationary sub-assembly of FIG. 6A from an
opposite side, according to some examples of the presently
disclosed subject matter;
[0066] FIG. 6C shows the stationary actuated sub-assembly in an
exploded view, according to some examples of the presently
disclosed subject matter;
[0067] FIG. 7 shows the actuator of FIG. 2B along a cut along line
A-B shown in FIG. 2A, according to some examples of the presently
disclosed subject matter;
[0068] FIG. 8 shows details of an electronic circuitry included in
the stationary sub-assembly of FIGS. 6A-6C, according to some
examples of the presently disclosed subject matter;
[0069] FIG. 9A shows a pitch actuation and sensing mechanism of the
actuator in FIGS. 2A-2B in an isometric view, according to some
examples of the presently disclosed subject matter;
[0070] FIG. 9B shows a side cut along a line A-B shown in FIG. 9A
of the pitch actuation and sensing mechanism of FIG. 9A, according
to some examples of the presently disclosed subject matter;
[0071] FIG. 10A shows a pitch actuation and sensing mechanism of
the actuator in FIGS. 2A-2B in an isometric view, according to
other examples of the presently disclosed subject matter;
[0072] FIG. 10B shows a side cut of the pitch actuation and sensing
mechanism of FIG. 10A along a line A-B shown in FIG. 10A, according
to some examples of the presently disclosed subject matter;
[0073] FIG. 11A shows a yaw sensing mechanism of the actuator in
FIGS. 2A-2B, according to some examples of the presently disclosed
subject matter;
[0074] FIG. 11B shows a yaw rotation range .beta., a distance
R.sub.YAW between a yaw Hall bar element and a yaw rotation axis,
and a trajectory of a yaw sensing magnet of the yaw sensing
mechanism of FIG. 11A in the Y-Z plane, according to some examples
of the presently disclosed subject matter;
[0075] FIG. 11C shows one magnetic configuration for the yaw
sensing magnet of FIG. 11B in a cut along a line A-B shown in FIG.
11A, according to some examples of the presently disclosed subject
matter;
[0076] FIG. 11D shows another magnetic configuration for the yaw
sensing magnet of FIG. 11B in a cut along a line A-B shown in FIG.
11A, according to some examples of the presently disclosed subject
matter;
[0077] FIG. 11E shows yet another magnetic configuration for the
yaw sensing magnet of FIG. 11B in a cut along a line A-B shown in
FIG. 11A, according to some examples of the presently disclosed
subject matter;
[0078] FIG. 11F shows the magnetic field as a function of rotation
along a given trajectory for the cases presented in FIGS. 11C-E,
according to some examples of the presently disclosed subject
matter;
[0079] FIG. 11-i to FIG. 11-vi show various possible alternative
examples of magnetic configuration for the yaw sensing magnet.
[0080] FIG. 12A shows a yaw magnetic actuation mechanism in an
isometric view from one side, according to some examples of the
presently disclosed subject matter
[0081] FIG. 12B shows the yaw magnetic actuation mechanism of FIG.
12A in an isometric view from another side, according to some
examples of the presently disclosed subject matter;
[0082] FIG. 12C shows magnetic field directions in a Y-Z plane
along a cut A-B in FIG. 12A, according to some examples of the
presently disclosed subject matter;
[0083] FIG. 13 shows additional magnetic yoke positioned next to
yaw magnet, according to some examples of the presently disclosed
subject matter;
[0084] FIG. 14A is a schematic illustration of a stitched image
generated from four Tele images, according to some examples of the
presently disclosed subject matter;
[0085] FIG. 14B is a schematic illustration of a stitched image
generated from six Tele images, according to some examples of the
presently disclosed subject matter;
[0086] FIG. 14C is a schematic illustration of a stitched image
generated from nine Tele images, according to some examples of the
presently disclosed subject matter;
[0087] FIG. 15A is a cross section of top actuated sub-assembly and
bottom actuated sub-assembly installed together along a cut along
line A-B shown in FIG. 15B, according to other examples of the
presently disclosed subject matter;
[0088] FIG. 15B is an isometric view of top actuated sub-assembly
and bottom actuated sub-assembly installed together of the example
shown in FIG. 15A, according to other examples of the presently
disclosed subject matter;
[0089] FIG. 15C is an isometric view of top actuated sub-assembly
and bottom actuated sub-assembly installed together, showing an
external yoke, according to other examples of the presently
disclosed subject matter;
[0090] FIG. 15D is a schematic illustration of a single
polarization magnet, according to some examples of the presently
disclosed subject matter; and
[0091] FIG. 15E is a schematic illustration of the magnetic field
lines directions in a Y-Z plane of the single polarization magnet
illustrated in FIG. 15D, according to some examples of the
presently disclosed subject matter.
DETAILED DESCRIPTION
[0092] For the sake of clarity, the term "substantially" is used
herein to imply the possibility of variations in values within an
acceptable range as would be known to a person skilled in the art.
According to one example, the term "substantially" used herein
should be interpreted to imply possible variation of up to 10% over
or under any specified value. According to another example, the
term "substantially" used herein should be interpreted to imply
possible variation of up to 5% over or under any specified value.
According to a further example, the term "substantially" used
herein should be interpreted to imply possible variation of up to
2.5% over or under any specified value. For example, the phrase
substantially perpendicular should be interpreted to include
possible variations from exactly 90.degree..
[0093] FIG. 1A illustrates a folded camera 100 with a 2
degrees-of-freedom (DOF) optical path folding element (OPFE) with
an extended rotation range, according to an example of the
presently disclosed subject matter. An orthogonal X-Y-Z coordinate
("axis") system shown applies also to all following drawings. This
coordinate system is exemplary only and should not be construed as
limiting. In some examples, the term "extended rotation range" used
herein is used to describe a rotation range larger than the 2-3
degrees necessary for another application, for example optical
image stabilization (OIS). In an example, an extended rotation
range may be a range equal to or greater than .+-.5 degrees in each
DOF relative to an OPFE zero state (as defined below). According to
another example, an extended rotation range may be a range equal to
or greater than .+-.10 degrees in each DOF relative to an OPFE zero
state (as defined below). According to yet another example, an
extended rotation range may be a range between .+-.15-40 degrees in
each DOF relative to an OPFE zero state (as defined below). The
extended rotation range may or may not be equal in the two DOF. In
an example, the extended rotation range may be twice or more in the
yaw DOF than in the pitch DOF, because the optical effect (shift of
image on the image sensor) of pitch rotation is double the optical
effect of yaw rotation.
[0094] Camera 100 includes a lens assembly or lens module (or
simply "lens") 102, an OPFE 104 and an image sensor 106. In general
lens module 102 comprises a plurality of lens elements positioned
along an optical axis, for example between 3 to 7 lens elements. In
some examples, lens 102 has a fixed focal length "f". In other
examples, lens 102 has a variable focal length (zoom lens). In some
examples, lens 102 may be a lens designed for folded cameras
described for example in co-owned U.S. Pat. No. 9,392,188. OPFE 104
has a reflection surface (e.g. it may be a mirror or a prism).
[0095] OPFE 104 folds light from a first optical path 108 to a
second optical path 110. First optical path 108 extends from the
direction of a view section 114 (facing an object or scene) towards
OPFE 104 and is substantially parallel to the X axis (in the
exemplary coordinate system). Second optical path 110 extends from
OPFE 104 towards image sensor 106 and is substantially parallel to
the Z axis (in the exemplary coordinate system).
[0096] View section 114 may include, for example, one or more
objects, a scene and/or a panoramic view, etc. According to the
illustrated example, axis 110 is aligned with the optical axis of
lens 102, and therefore is also referred to herein as "lens optical
axis" Image sensor 106 may be aligned with a plane substantially
perpendicular to axis 110 (a plane that includes the X and Y axes).
Image sensor 106 may output an output image. The output image may
be processed by an image signal processor (ISP--not shown), the
processing including for example, demosaicing, white balance, lens
shading correction, bad pixel correction and other processes that
may be carried out by an ISP. In some embodiments, the ISP (or some
functionalities of the ISP) may be part of image sensor 106.
[0097] It is noted that while the OPFE and some of the parts
described below may be configured to rotate in two DOF, all the
figures, the description and the directions therein show the OPFE
in a "zero" state (without rotation) unless otherwise
mentioned.
[0098] For the sake of clarity of the description and by way of a
non limiting example only, it is defined that at zero state the
first optical path 108 extending from the direction of view section
114 towards the OPFE 104 is perpendicular to a zero plane. The term
"zero plane" as used herein refers to an imaginary plane on which
an actuator 202 described below is positioned and is parallel to
the lens optical axis. For example, in a mobile phone, the zero
plane is a plane parallel to the screen of the phone.
[0099] Furthermore, in zero state the reflecting surface of the
OPFE is positioned such that light along the first optical path 108
is redirected to a second optical path 108 that coincides with lens
optical axis 110. Notably, the above definition is assumed to be
true for the center of the field of view (FOV).
[0100] Yaw rotation can be defined as rotation around an axis
substantially parallel to the first optical path in zero state.
Pitch rotation can be defined as rotation around an axis
substantially perpendicular to the yaw rotation axis and the lens
optical axis.
[0101] In some examples, camera 100 may further include a focus or
autofocus (AF) mechanism (not shown), allowing to move (or "shift"
or "actuate") lens 102 along axis 110. The AF mechanism may be
configured to adjust the focus of the camera on view section 114.
Adjusting the focus on view section 114 may bring into focus one or
more objects and/or take out of focus one or more objects that may
be part of view section 114, depending on their distance from OPFE
104. For simplicity, the description continues with reference only
to AF mechanisms, with the understanding that it also covers
regular (manual) focus.
[0102] An AF mechanism may comprise an AF actuation mechanism. The
AF actuation mechanism may comprise a motor that may impart motion
such as a voice coil motor (VCM), a stepper motor, a shape memory
alloy (SMA) actuator and/or other types of motors. An AF actuation
mechanism that comprises a VCM may be referred to as a "VCM
actuator". Such actuation mechanisms are known in the art and
disclosed for example in Applicant's co-owned international patent
applications PCT/IB2015/056004 and PCT/IB2016/055308. In some
embodiments, camera 100 may include an optical image stabilization
(OIS) actuation mechanism (not shown) in addition to, or instead
of, the AF actuation mechanism. In some embodiments, OIS may be
achieved by shifting lens 102 and/or image sensor 106 in one or
more directions in the X-Y plane, compensating for tilt of camera
100 around the Z and Y directions. A three-degrees of freedom
(3-DOF) OIS and focus actuation mechanism (which performs two
movements for OIS and one for AF) may be of VCM type and known in
the art, for example as disclosed in international patent
application PCT/US2013/076753 and in US patent application
2014/0327965. In other embodiments, OIS may be achieved by shifting
the lens in one direction (i.e. the Y direction), perpendicular to
both the first and second optical paths, compensating for tilt of
camera 100 around the Z direction (lens optical axis). In this
case, a second OIS operation, compensating for tilt of camera 100
around the Z direction may be done by tilting the OPFE around the Y
axis, as demonstrated below. More information on auto-focus and OIS
in a compact folded camera may be found in Applicant's co-owned
international patent applications PCT/IB2016/052143,
PCT/IB2016/052179 and PCT/IB2016/053335.
[0103] Camera 100 is designed with a capability to rotate OPFE 104
with at least two DOF (2-DOF) in an extended rotation range.
Rotation can be done for example using OPFE actuator 120, seen in
FIG. 1B. Two-DOF rotation may be used to describe rotation of the
prism around two axes (each axis being a DOF); in camera 100, the
degrees of freedom are a yaw rotation 132 around yaw rotation axis
122 which is parallel to first optical path 108 (X axis) when in
zero state as defined above, and a pitch rotation 134 around a
pitch rotation axis 124 which is parallel to the Y axis. In camera
100, yaw rotation axis 122 and pitch rotation axis 124 may
intersect, which may reduce coupling between a pitch sensing
mechanism and yaw rotation, as described below with reference to
FIG. 9. In camera 100, lens optical axis 110 intersects the
intersection point of yaw rotation axis 122 and pitch rotation axis
124. In other embodiments, this may not be the case.
[0104] As shown in FIG. 1C, camera 100 may be a part of a
dual-camera 180. Dual-camera 180 comprises camera 100 and an
upright camera 190. Upright camera 190 includes a lens 192 and an
image sensor 194. Upright camera 190 may further include other
parts such as a shield, a focus or AF mechanism, and/or an OIS
mechanism (all of which are not shown), as known in the art.
Cameras 100 and 190 may share some or all of respective fields of
view (FOVs). According to some examples, camera 190 may have a
wider FOV than camera 100. In such an example, camera 100 will be
referred as a "Tele camera", while camera 190 will be referred as a
"Wide camera". In such an example, a scanning mechanism of camera
100 may be used to cover some or all of the FOV of camera 190, as
explained in the description below of FIGS. 14A-14C. In other
examples, camera 100 may be a part of a multiple aperture camera
(multi-camera) comprising more than two cameras, e.g. comprising
two or more additional upright and/or two or more additional folded
cameras. Notably, while characterized by extended rotation ranges,
camera 100 and actuator 120 may also be capable of performing small
range (1-2 degree) actuations with high accuracy, which enable OIS
around any position in the extended rotation range.
[0105] FIGS. 2A-B show OPFE actuator 120 with more details
according to some non-limiting examples of the presently disclosed
subject matter. FIG. 2A shows OPFE actuator 120 in an isometric
view. OPFE actuator 120 may be covered by a shield 202 with an
opening 204 through which light can enter into OPFE 104 and an
opening 206 through which light can exit from OPFE 104. FIG. 2B
shows actuator 120 without shield 202. Actuator 120 further
includes a bottom actuated sub-assembly 220 (also referred to
herein as "yaw sub-assembly" or "first sub-assembly"), a top
actuated sub-assembly 210 (also referred to herein as "pitch
sub-assembly" or "second sub-assembly"), and a stationary
sub-assembly 230. Top actuated sub-assembly 210 may be operable to
be rotated, and thus rotate OPFE 104, around the pitch rotation
axis (parallel to the Y axis) relative to bottom actuated
sub-assembly 220 (pitch rotation 134), as described below. Bottom
actuated sub-assembly 220 may be operable to be rotated, and thus
rotate OPFE 104, around the yaw rotation axis (parallel to the X
axis) relative to stationary sub-assembly 230 (yaw rotation 132),
as described below.
[0106] As described in more detail below, according to one example,
the bottom (yaw) actuated sub-assembly 220 rotates relative to a
stationary sub-assembly and the top (pitch) actuated sub-assembly
210 rotates relative to the bottom sub-assembly, thus the bottom
sub-assembly acts as a master and the top sub-assembly acts as a
slave. Applicant has found that this design, with the bottom
actuated sub-assembly used for yaw rotation and the top actuated
sub-assembly used for pitch rotation, and with the bottom actuated
sub-assembly serving as a master and the top actuated sub-assembly
serving as a slave, enables to maintain a lower overall height of
the actuator and thus to mitigate a penalty on the folded camera
height.
[0107] FIGS. 3A-C show top (pitch) actuated sub-assembly 210 with
more details in an isometric view from one side (FIG. 3A), an
isometric view from another side (FIG. 3B), and an exploded view
(FIG. 3C), according to some non-limiting examples of the presently
disclosed subject matter. Top actuated sub-assembly 210 includes an
OPFE holder (or carrier) 302 that can be made, for example, by a
plastic mold that fits the shape of OPFE 104. Top actuated
sub-assembly 210 further includes a permanent (fixed) pitch magnet
304. Pitch magnet 304, as well as all other magnets in this
application, can be for example a permanent magnet, made from a
neodymium alloy (e.g. Nd.sub.2Fe.sub.14B) or a samarium-cobalt
alloy (e.g. SmCo.sub.5), and can be made by sintering. According to
one example, pitch magnet 304 is fixedly attached (e.g. glued) to
OPFE carrier 302 from below (negative X direction in FIG. 3A).
Hereinafter, the term "below" used with reference to the position
of OPFE 104 refers to a side of the OPFE opposite to the side
facing the view section (in the negative X direction relative to
the view). Details of pitch magnet 304 and its operation are given
below. In some examples, OPFE carrier 302 includes (e.g. is molded
with) two pins 308.
[0108] Sub-assembly 210 may further include two ferromagnetic yokes
306. Ferromagnetic yokes 306 may be attached (e.g. glued) to OPFE
holder 302 on pins 308. Ferromagnetic yokes 306 may be made of a
ferromagnetic material (e.g. iron) and have an arced (curved) shape
with a center on pitch rotation axis 124. Ferromagnetic yokes 306
are pulled by pitch-pull magnets 408 (see FIGS. 4A, 4C) to attach
top actuated sub-assembly 210 to bottom actuated sub-assembly 220
as described below with reference to FIGS. 5A-5C. OPFE holder 302
may further include (e.g. is molded with) two parallel arc-shaped
(curved) grooves 310a and 310b (FIG. 3B) positioned at two opposite
sides of OPFE holder 302, each arc-shaped groove having an angle
.alpha.'>.alpha., where angle .alpha. is a desired pitch stroke,
as defined by optical needs. Angle .alpha.' is shown in FIG. 5B.
Arc-shaped grooves 310a and 310b have a center of curvature on
pitch rotation axis 124 (see FIGS. 3A, 5A, 5B). OPFE holder 302
further includes (e.g. is molded with) two stoppers 312 (FIG. 3A)
positioned at two opposite sides of OPFE holder 302. Stoppers 312
are used to stop OPFE 104 in a required position.
[0109] FIGS. 4A-C show bottom (yaw) actuated sub-assembly 220 with
more details in an isometric view from one side (FIG. 4A), an
isometric view from another side (FIG. 4B), and an exploded view
(FIG. 4C). Bottom actuated sub-assembly 220 includes a middle
moving frame 402 which can be made, for example, by a plastic mold.
Bottom actuated sub-assembly 220 further included four permanent
(fixed) magnets: a yaw actuation magnet 404, a yaw sensing magnet
406, and two pitch-pull magnets 408. All magnets are fixedly
attached (e.g. glued) to middle moving frame 402. Notably, yaw
magnet 404 is located on a side of the OPFE that is opposite to the
side facing lens module 102 in camera 100. Details of all magnets
and their operation are given below.
[0110] Bottom actuated sub-assembly 220 further includes two
stoppers 410, made for example from a non-magnetic metal. Stoppers
410 are fixedly attached (e.g. glued) to middle moving frame 402.
Stoppers 410 help to prevent top actuated sub-assembly 210 from
detaching from bottom actuated sub-assembly 220 in case of a strong
external impact or drop, as described in more detail below. Middle
moving frame 402 includes (i.e. is molded with) two parallel
arc-shaped (curved) grooves 412 (FIG. 4A) positioned at two
opposite sides of middle moving frame 402, each arc-shaped groove
having an angle .alpha.''>.alpha.. Angle .alpha.'' is shown in
FIG. 5B. Arc-shaped grooves 412 have a center of curvature on yaw
rotation axis 122 (FIG. 5B) in common with arc shaped grooves 310.
Middle moving frame 402 further includes (e.g. is molded with) two
parallel arc-shaped (or "curved") grooves 414 (FIG. 4B) positioned
at a back side of middle moving frame 402 (negative Z axis), each
arc-shaped groove having an angle .beta.'>.beta., where angle
.beta. is a required yaw stroke, as defined by optical needs. Angle
.beta.' is shown in FIG. 7. Arc-shaped grooves 414 have a center of
curvature on yaw rotation axis 122 (FIG. 7).
[0111] FIGS. 5A-B show top actuated sub-assembly 210 and bottom
actuated sub-assembly 220 installed together. FIG. 5A shows an
isometric view and FIG. 5B shows a cut along line A-B in FIG. 5A.
The figures also show various elements described above. FIG. 5B
shows actuator 120 with three balls 512a, 514a and 516a positioned
in the space between grooves 310a and 412a, and three balls 512b,
514b and 516b positioned in the space between grooves 310b and
412b. FIG. 5B shows only balls 512b, 514b and 516b and grooves 310b
and 412b, while balls 512a, 514a and 516a and grooves 310a and 412a
are not seen (being in the unseen back side of the drawing), with
understanding of them being symmetric along plane Z-Y. The number
of balls (here 3) shown in the drawing is for the sake of example
only and should not be construed as limiting. In other embodiments,
an actuator such as actuator 120 may have more or fewer of three
balls (e.g. 2-7 balls) in the space between adjacent grooves. The
balls may be made of Alumina, another ceramic material, metal,
plastic or other suitable materials. The balls may have for example
a diameter in the range of 0.3-1 mm. In actuator 120, grooves 310a,
301b, 412a, 412b and balls 512a, 512b, 514a, 514b, 516a and 516b
form a curved ball-guided mechanism 560 operative to impart a
rotation or tilt movement to an optical element (e.g. OPFE 104)
upon actuation by the VCM actuator (see below). More details on
ball-guided mechanisms in actuators may be found in co-owned
international patent applications PCT/IB2017/052383 and
PCT/IB2017/054088.
[0112] In some embodiments, balls having different sizes (e.g. two
different ball sizes) may be used to provide smoother motion. The
balls can be divided into a large diameter (LD) group and a small
diameter (SD) group. The balls in each group may have the same
diameter. LD balls may have for example a 0.1-0.3 mm larger
diameter than SD balls. A SD ball may be positioned between two LD
balls to maintain the rolling ability of the mechanism. For
example, balls 512b and 516b may be LD balls and ball 514b may be a
SD ball (and similarly for balls 512a-516a). As described above,
two metallic ferromagnetic yokes 306 that may be fixedly attached
to OPFE holder 302 face two pitch-pull magnets 408 that may be
attached to middle frame 402. Ferromagnetic yokes 306 may pull
magnets 408 (and thus pull top actuated sub-assembly 210 to bottom
actuated sub assembly 220) by magnetic force and hold a curved
ball-guided mechanism 560 from coming apart. The magnetic force
(e.g. acting between yoke 306 and magnets 408) that is used for
preventing two parts of a moving mechanism to be detached is
referred to herein as "pre-load force". A pitch-pull magnet 408 and
its respective yoke 306 may be referred to as "first magnet-yoke
pair". Ferromagnetic yokes 306 and pitch-pull magnets 408 both have
arc shapes, with a center on pitch rotation axis 124. The magnetic
direction of pitch-pull magnets 408 is along pitch rotation axis
124, e.g. with a north pole toward OPFE 104 and a south pole away
from OPFE 104. Due to the geometric and magnetic design presented,
the magnetic force (pre-load force) between ferromagnetic yokes 306
and pitch-pull magnets 408 is kept substantially in a radial
direction 520 with a center on pitch rotation axis 124, and
negligible tangent force, at all rotation positions, as can be seen
in FIG. 5A.
[0113] Balls 512a-516a and 512b-516b prevent top actuated
sub-assembly 210 from touching bottom actuated sub-assembly 220.
Top actuated sub-assembly 210 is thus confined with a constant
distance from bottom actuated sub-assembly 220. Curved ball-guided
mechanism 560 further confines top actuated sub-assembly 210 along
pitch rotation axis 124. Top actuated sub-assembly 210 can only
move along the path defined by curved ball-guided mechanism 560,
namely in a pitch rotation 134 around pitch rotation axis 124.
[0114] FIGS. 6A-C show stationary sub-assembly 230 with more
details, in an isometric view from one side (FIG. 6A), an isometric
view from another side (FIG. 6B) and an exploded view (FIG. 6C).
Stationary sub-assembly 230 includes a base 602 that can be made,
for example, by plastic mold. Stationary sub-assembly 230 further
includes electronic circuitry 608 attached to base 602, shown in
FIG. 6C. Details of electronic circuitry 608 are given below with
reference to FIG. 8. Stationary sub-assembly 230 further includes a
ferromagnetic yoke 606. Ferromagnetic yoke 606 is made by
ferromagnetic material (e.g. iron) and is pulled by yaw actuation
magnet 404 (see FIGS. 6B and 7C) to attach bottom actuated
sub-assembly 220 to stationary sub-assembly 230 as described in
more detail below. Ferromagnetic yoke 606 and yaw actuation magnet
404 may be referred to as "second magnet-yoke pair".
[0115] Stationary actuated sub-assembly 230 further include a
stopper 610. Stopper 610 is made for example from a non-magnetic
metal. Stopper 610 is attached (e.g. glued) to based 602. Stopper
610 helps to prevent bottom actuated sub-assembly 220 from
detaching from base 602 in case of a strong external impact or
drop, as described in more detail below. In some examples, base 602
includes (i.e. is molded with) two parallel arc-shaped (curved)
grooves 612a-d (FIG. 6A), each arc-shaped groove having an angle
.beta.''>.beta., where angle .beta. is a required tilt stroke,
as defined by optical needs. Angle .beta.'' is shown in FIG. 7.
Arc-shaped grooves 612a-d may further include a center of curvature
on yaw rotation axis 122 (FIGS. 2C, 6A and 7), in common with
arc-shaped grooves 414a-b.
[0116] FIG. 7 shows actuator 120 without the shield along a cut
along line A-B seen in FIG. 2A. Grooves 612a-d are shown to share a
center with grooves 414a-b on yaw rotation axis 122 (612c and 612d,
which are shown in FIGS. 6B and 6C are hidden in FIG. 7). Angles
.beta.' and .beta.'' are demonstrated. Groves 612a-b are adjacent
to groove 414a while grooves 612c-d are adjacent to groove 414b.
Four balls 712 (two are shown in FIG. 7) are positioned between
adjacent groove pairs 612a and 414a, 612b and 414a, 612c and 414b,
and 612d and 414b, one ball between each adjacent groove pair. In
other embodiments, actuator 120 may have more than one ball pair in
each adjacent groove pair, e.g. in the range of 1-4 balls. The
considerations for size and materials of all balls are similar to
those described above. Grooves 414a-b, 612a-d and balls 712 form a
second curved ball-guided mechanism 760 of actuator 120. As shown
in FIG. 6 and FIG. 7, the second curved ball-guided mechanism is
situated such that the grooves 612 for rotating around the yaw axis
are located behind OPFE 104 i.e. in the positive direction along
the Z axis relative to OPFE 104 (a side opposite to the side facing
the lens module).
[0117] As described above, ferromagnetic yoke 606 is fixedly
attached to base 602 facing magnet 404 (illustrated for example in
FIG. 4a and FIG. 4c). Ferromagnetic yoke 606 pulls magnet 404 (and
thus pulls bottom actuated sub-assembly 220) to stationary
sub-assembly 230 by magnetic force 702 (pre-load force) and thus
holds curved ball-guided mechanisms 760 from coming apart. The
direction of magnetic force 702 is marked in FIG. 7 as the Z
direction. Balls 712 prevent bottom actuated sub-assembly 220 from
touching stationary sub-assembly 230. Bottom actuated sub-assembly
220 is thus confined with a constant distance from stationary
sub-assembly 230. Second curved ball-guided mechanism 760 further
confines bottom actuated sub-assembly 220 along the Y-axis. Bottom
actuated sub-assembly 220 can only move along the path defined by
the curved ball-guided mechanism 760, namely in a yaw rotation
around yaw rotation axis 122.
[0118] The curved ball-guided mechanisms 560 and 760 disclosed
herein provides flexibility when defining the pitch and yaw
rotation axes respectively, as the curve can be adapted to the
required rotation axis. Furthermore, curved ball-guided mechanisms
560 and 760 enable to execute movement of the top actuated
sub-assembly and the bottom actuated sub-assembly by rolling over
the balls confined within the grooves (rails) along the path
prescribed by the grooves, and thus help to reduce or eliminate
friction that may otherwise exist during movement between the balls
and the moving parts.
[0119] FIG. 8 shows electronic circuitry 608 with more details,
according to some examples of the presently disclosed subject
matter. Electronic circuitry 608 includes a printed circuit board
(PCB) 802 and may include processing circuitry. PCB 802 allows
sending input and output currents to coils 806 and 804 and to Hall
bar elements 808 and 810 (described below), the currents carrying
both power and electronic signals needed for operation. PCB 802 may
be connected electronically to host camera (camera 100 or similar
cameras) or host device (e.g. phone, computer, not shown) e.g. by
wires (not shown). PCB 802 may be a flexible PCB (FPCB) or a rigid
flex PCB (RFPCB) and may have several layers (e.g. 2-6) as known in
the art. Electronic circuitry 608 further includes three coils, a
pitch coil 804 and two yaw coils 806. Electronic circuitry 608
further includes two Hall bar sensing elements, a pitch Hall bar
element 808 and a yaw Hall bar element 810. Coils 804 and 806 and
Hall bar elements 808 and 810 are all connected (e.g. soldered) to
PCB 802. In actuator 120, pitch coil 804 and pitch Hall bar element
808 are positioned below pitch magnet 304. Notably, some of the
components mentioned as part of the electronic circuitry are also
considered as part of an actuation and sensing mechanism.
[0120] Notably, yaw rotation axis 122 is positioned as closely as
possible to the pitch sensor (e.g. Hall bar element 808). According
to one example, yaw rotation axis 122 passes through pitch sensor
808, in order to decouple the sensing of the pitch sensor from the
rotation around the yaw axis. When decoupled, the influence on the
sensing of the pitch sensor by rotation around the yaw axis is
reduced or eliminated. More specifically, according to one example,
yaw rotation axis 122 passes through the center of pitch sensor
808. By positioning the yaw rotation axis so it passes through the
center of the pitch sensor, the influence of yaw rotation on the
sensing of pitch sensor can be completely eliminated. In addition,
in some designs, yaw rotation axis 122 may optionally pass through
the center of pitch coil 804.
[0121] FIGS. 9A-B show an example of a pitch actuation and sensing
mechanism (PAASM) 900 that includes pitch magnet 304, pitch coil
804 and pitch Hall bar element 808. PAASM 900 may be included in
actuator 120. In some embodiments, PAASM 900 may be used only for
actuation (acting as an actuation mechanism for one DOF). FIG. 9A
shows PAASM 900 in an isometric view and FIG. 9B shows a side cut
of pitch magnet 304 along a line A-B. According to one example,
pitch magnet 304 may be symmetric along a plane that includes pitch
rotation axis 124 and first optical axis 108. In an example, pitch
magnet 304 may be fabricated (e.g. sintered) such that it has a
changing magnetic field direction along its mechanical symmetry
plane, e.g. a north magnetic field facing the positive X direction
on the left side and a north magnetic field facing the negative X
direction on the right side. Pitch magnet 304 may have a length
R.sub.PITCH of a few millimeters (for example 2-6 mm) in parallel
to pitch rotation axis 124 and substantially longer than pitch coil
804, such that its magnetic field on most lines parallel to pitch
rotation axis 124 may be considered constant. Upon driving a
current in pitch coil 804, a Lorentz force is created on pitch
magnet 304; a current in a clockwise direction will create force in
the positive Z direction (along the Z axis), while a current in
counter clockwise direction will create a force in the negative Z
direction. Any force on pitch magnet 304 is translated to torque
around pitch rotation axis 124, and thus top actuated subassembly
210 will rotate relative to bottom actuated sub-assembly 220.
[0122] Pitch Hall bar element (sensor) 808, which is positioned
inside pitch coil 804, can sense the intensity and direction of the
magnetic field of pitch magnet 304 radially directed away from
pitch rotation axis 124. In other words, for any pitch orientation
of top actuated sub-assembly 210, pitch Hall bar measures the
intensity of the magnetic field directed in the X direction only.
Since yaw rotation axis 122 passes through pitch Hall bar element
808, the effect of the yaw rotation of bottom actuated sub-assembly
220 on the magnetic field in the X direction applied by pitch
magnet 304 is reduced (e.g. eliminated) and thus any change on the
measurement of pitch Hall bar element 808 is reduced (e.g.
eliminated) as well. By positioning the Hall bar element 808 such
that the yaw rotation axis 122 passes through its center, the
effect of the yaw rotation of bottom actuated sub-assembly 220 on
the magnetic field in the X direction applied by pitch magnet 304
is reduced (e g minimized) and thus any change on the measurement
of pitch Hall bar element 808 is mitigated. Pitch Hall bar element
808 can thus measure the respective pitch rotation of top actuated
sub-assembly 210 while being unaffected by the yaw rotation of
bottom actuated sub-assembly.
[0123] FIGS. 10A-B show another exemplary embodiment of a PAASM
numbered 1000, similar to PAASM 900. PAASM 1000 may be included in
actuator 120, to replace PAASM 900. According to one example, a
pitch magnet 1004 replaces pitch magnet 304. Pitch magnet 1004 is a
cut of a sphere with its center positioned substantially on the
intersection point of yaw rotation axis 122 and pitch rotation axis
124. According to one example, a pitch coil 1006 that replaces
pitch coil 804 has a circular shape with a center substantially on
yaw rotation axis 122 (in some examples the yaw rotation axis
passes exactly through the center of the coil). Pitch coil 1006 may
be made (fabricated) with similar considerations presented above
for pitch coil 804. Due to the symmetry of the pitch magnet around
yaw rotation axis 122, any yaw rotation will not influence the
magnetic field of the pitch coil and thus will not change the force
applied by pitch coil 1006 on pitch magnet 1004. Having a constant
force for various yaw positions may facilitate and simplify pitch
position control (close loop control or open loop control). As
mentioned above, yaw rotation axis passes through sensor 808 to
thereby reduce the effect of yaw rotation of bottom actuated
sub-assembly 220 on the magnetic field in the X direction applied
by pitch magnet 1004.
[0124] FIG. 11A shows a yaw sensing mechanism numbered 1100. Yaw
sensing mechanism 1100 includes yaw sensing magnet 406 and yaw Hall
bar element 810. Yaw Hall bar element 810 can measure the intensity
and direction of the magnetic field of yaw sensing magnet 406
directed along yaw rotation axis 122. In other words, Hall bar
element 810 measures the intensity of magnetic field directed in
the X direction only.
[0125] FIG. 11B shows a yaw rotation range .beta., a distance
R.sub.YAW between yaw Hall bar element 810 and yaw rotation axis
122, and a trajectory 1108 of yaw sensing magnet 406 in the Y-Z
plane. In some examples, yaw rotation range .beta. is more than 10
degrees. The distance R.sub.YAW is e.g. in the range of 2-5 mm. As
an example, a case in which .beta.=40.degree. (meaning
.+-.20.degree. from the "zero" position) and R.sub.YAW=2.75 mm is
analyzed in FIGS. 11C-F below. As bottom actuated sub-assembly 220
is yaw-rotated, trajectory 1108 is in the Y-Z plane. Trajectory
1108 has an arc projection in the Y-Z plane (FIG. 11B) with length
.beta..times.R.sub.YAW, where .beta. is calculated in radians.
Trajectory 1108 has a line shape projection on the X-Y plane (FIGS.
11C-E) with Length 2.times.R.sub.YAW.times.cos(.beta.).
[0126] Yaw sensing magnet 406 is designed such that is has
dimensions along Z-Y directions and such that it covers trajectory
1108 from the top view (Y-Z plane). Yaw sensing magnet 406 can have
different configurations.
[0127] FIGS. 11C-E show three different examples of magnetic
configurations for yaw sensing magnet 406 in a cross section along
X-Y plane of yaw sensing mechanism 1100. In the configuration of
FIG. 11C, yaw sensing magnet 406 has a rectangular cross section
and the magnetic field of yaw sensing magnet 406 changes direction
in the middle, e.g. the north magnetic field facing the positive X
direction on the left side and the north magnetic field facing the
negative X direction on the right side. In the configuration of
FIG. 11D, yaw sensing magnet 406 has a rectangular cross section,
and the magnetic field of yaw sensing magnet 406 is directed in the
Y direction.
[0128] In the configuration shown in FIG. 11E, yaw sensing magnet
406 is characterized, along the Y direction, by a thinner cross
section (the Y-X plane) in the middle and a thicker cross section
on the sides. The varying width results in a varying distance
between the sensor and the magnet positioned near the magnet (the
sensor is located towards the negative X direction relative to the
magnet) and thus a varying magnetic field along a projection of
trajectory 1108 (line 1114) on the Y-X plane. In some examples, the
variation around the magnetic field is symmetrical around its
center such that the thickness of the cross section of the magnet
increases from a point substantially at its center towards each end
of the magnet. Various examples of magnets constructed according to
this principle are illustrated in FIGS. 11-i to 11-vi.
[0129] In addition, in some examples of the configuration of FIG.
11E (or any one of FIGS. 11-i to 11-vi), the magnetic field of yaw
sensing magnet 406 changes direction in the middle, e.g. the north
magnetic field faces the positive X direction on the left side and
the north magnetic field faces the negative X direction on the
right side. This results in zero magnetic field in the X direction
in yaw hall bar element 810 facing the center of magnet 406 (along
the center line).
[0130] FIG. 11F shows the magnetic field as a function of rotation
along trajectory 1108, for the 3 cases presented in FIGS. 11C-E.
The projection of trajectory 1108 on plane X-Y (representing a
lateral shift component of the magnet shift relative to the sensor)
is shown by line 1110 in FIG. 11C, line 1112 in FIG. 11D and line
1114 in FIG. 11E. For line 1110, the maximal magnetic field change
along .+-.20 degrees trajectory is .+-.0.28 Tesla. However, most of
the magnetic field change is obtained in a .+-.7 degrees trajectory
and the magnetic field gradient at higher yaw angles is lower than
at lower yaw angles. This limits the ability to sense changes with
high accuracy in high yaw angles. For projection line 1112, the
magnetic field gradient is more uniform along the trajectory of
.+-.20, comparing to projection line 1110. However, the magnetic
field total change is limited to under .+-.0.08 Tesla. For
projection line 1114 the magnetic field gradient is more uniform
than for both lines 1110 and 1112, and the total magnetic field
change is .+-.0.25 Tesla, which can give high accuracy for position
measurements. Thus, the magnetic configuration presented in FIG.
11E is superior for position sensing at large strokes, relative to
the distance between the Hall bar and the corresponding magnet
(e.g. in 1-4 mm range) using changes in magnetic field. Thus, by
shaping the magnet with a variable thickness as shown in FIGS. 11E
and 11-i to 11-vi, the range of detectable change in magnetic flux
in increased. Accordingly, the corresponding detectable range of
relative (lateral) shift of the magnet and sensor is increased as
well.
[0131] FIG. 12A-C shows a yaw magnetic actuation mechanism numbered
1200. This actuation mechanism is for a second DOF. FIG. 12A show
isometric view from one side, FIG. 12B shows isometric view from
another side. Yaw magnetic actuation mechanism 1200 include yaw
actuation magnet 404, yaw coils 806 and ferromagnetic yoke 606.
FIG. 12C shows the magnetic field directions is Y-Z plane, along a
cut A-B in FIG. 12A. Yaw actuation magnet 404 may be sintered such
that its magnetic field is pointed toward negative Z direction.
Each of coils 806 has one part (1202, 1204) which is positioned in
close proximity to yaw actuation magnet 404 (e.g. distance of
100-300 .mu.m), and one part (1206, 1208) which is further apart
from yaw magnet 404. Coils 806 may be connected in serial, such
that the current in the two coil is equal. When current in 1202 is
in the positive X direction the current in 1204 is also in the
positive X direction, and the current in parts 1206 and 1208 is in
the negative X direction. Upon driving a current in Yaw coils 806,
a Lorentz force is created on the yaw magnet 404, according to
d{right arrow over (F)}=Id{right arrow over (l)}.times.{right arrow
over (B)}. The direction of the magnetic field is demonstrated in
FIG. 12C. The Lorentz force is translated into torque around yaw
rotation axis 122.
[0132] In some examples, an additional magnetic yoke 1302 may be
located next to yaw magnet 404. This yoke may increase the
intensity of the magnetic field in coils 806 and increase the
torque created by yaw magnetic actuation mechanism 1200. FIG. 13
shows this case.
[0133] In some examples, rotation of the reflecting element around
one or two axes moves the position of the camera FOV, wherein in
each position a different portion of a scene is captured in an
image having the resolution of the digital camera. In this way a
plurality of images of adjacent camera FOVs (e.g. partially
overlapping FOVs) are captured and stitched together to form a
stitched (also referred to as "composite") image having an overall
image area of an FOV greater than digital camera FOV.
[0134] In some examples the digital camera can be a folded Tele
camera configured to provide a Tele image with a Tele image
resolution, the folded Tele camera comprising a Tele image sensor
and its Tele lens assembly is characterized with a Tele field of
view (FOV.sub.T). According to some examples, the folded Tele
camera is integrated in a multiple aperture digital camera that
comprises at least one additional upright Wide camera configured to
provide a Wide image with a Wide image resolution, being smaller
than the Tele image resolution, the Wide camera comprising a Wide
image sensor and a Wide lens module with a Wide field of view
(FOV.sub.W); wherein FOV.sub.T is smaller than FOV.sub.W, wherein
rotation of the OPFE moves FOV.sub.T relative to FOV.sub.W, for
example as shown in of co-owned international patent applications
PCT/IB2016/056060 and PCT/IB2016/057366.
[0135] The description of these PCT applications includes a Tele
camera with an adjustable Tele field of view. As described in
PCT/IB2016/056060 and PCT/IB2016/057366, rotation of the reflecting
element around one or two axes moves the position of Tele FOV
(FOV.sub.T) relative to the Wide FOV (FOV.sub.W), wherein in each
position a different portion a scene (within FOV.sub.W) is captured
in a "Tele image" with higher resolution. According to some
examples, disclosed in PCT/IB2016/056060 and PCT/IB2016/057366, a
plurality of Tele images of adjacent non-overlapping (or partially
overlapping) Tele FOVs are captured and stitched together to form a
stitched (also referred to as "composite") Tele image having an
overall image area of an FOV greater than FOV.sub.T. According to
some examples, the stitched Tele image is fused with the Wide image
generated by the Wide camera.
[0136] Digital camera 100 can further comprise or be otherwise
operatively connected to a computer processing circuitry
(comprising one or more computer processing devices), which is
configured to control the operation of the digital camera (e.g.
camera CPU). The processing circuitry, can comprise for example a
controller operatively connected to the actuator of the rotating
OPFE configured to control its operation.
[0137] The processing circuitry can be responsive to a command
requesting an image with a certain zoom factor and control the
operation of the digital camera for providing images having the
requested zoom. As mentioned in applications PCT/IB2016/056060 and
PCT/IB2016/057366, in some examples a user interface (executed for
example by the processing circuitry) can be configured to allow
input of user command being indicative of a requested zoom factor.
The processing circuitry can be configured to process the command
and provide appropriate instructions to the digital camera for
capturing images having the requested zoom.
[0138] In some cases, if the requested zoom factor is a value
between the FOV.sub.W of a wide camera and FOV.sub.T of a tele
camera, the processing circuitry can be configured to cause the
actuator of the reflecting element to move the reflecting element
(by providing instruction to the controller of the actuator) such
that a partial area of the scene corresponding to the requested
zoom factor is scanned and a plurality of partially overlapping or
non-overlapping Tele images, each having a Tele resolution and
covering a portion of the partial area, are captured. The
processing circuitry can be further configured to stitch the
plurality of captured imaged together in order to form a stitched
image (composite image) having Tele resolution and an FOV greater
than the FOV.sub.T of the digital camera. Optionally the stitched
image can then be fused with the Wide image.
[0139] FIG. 14A is a schematic illustration of an example of a
stitched image 1400 generated by scanning, capturing and stitching
together four Tele images with FOV.sub.T, compared to the FOV.sub.W
of a Wide camera, as in the example of FIG. 1C, where camera 190
represents a Wide FOV camera with a FOV.sub.W coupled to folded
Tele camera 100 with a FOV.sub.T. In FIG. 14A, 1402 denotes
FOV.sub.W, 1404 denotes FOV.sub.T at the center of FOV.sub.W and
1406 indicates the size of the requested zoom factor. In the
illustrated example, four partially overlapping Tele images 1408
are captured.
[0140] Notably, the overall area of captured Tele images 1408 is
greater than the area of the zoom image 1406 in the requested zoom.
The central part of the captured Tele images is extracted (e.g. by
the computer processing circuitry as part of the generation of the
stitched image) for generating stitched image 1400. This helps to
reduce the effect of image artefacts resulting from transition from
an image area covered by one image to an image area covered by a
different image.
[0141] FIG. 14B is a schematic illustration of an example of a
stitched image 1400' generated by capturing and stitching together
six Tele images. FIG. 14C is a schematic illustration of an example
of a stitched image 1400' generated by capturing and stitching
together nine Tele images. The same principles described with
reference to FIG. 14A apply to FIGS. 14B and 14C. Notably, the
output image resulting from the stitching can have a different
width to height ratio than the single image proportion. For
example, as illustrated in FIG. 14B, a single image can have a 3:4
ratio and the output stitched image can have a 9:16 ratio.
[0142] It is noted that image stitching per se is well known in the
art and therefore it is not explained further in detail.
[0143] An alternative design of the top and bottom actuated
sub-assemblies described above is now described with reference to
FIGS. 15A-15E. Notably, as would be apparent to any person skilled
in the art, unless stated otherwise, some of the details described
above with reference to the previous figures can also be applied to
the example described with reference to FIGS. 15A-15E.
[0144] According to this design, a single magnet 1510 serves for
three purposes: 1) as a pre-load magnet in magnet-yoke pair,
dedicated for fastening the bottom actuated sub-assembly to the
stationary sub-assembly; 2) as a yaw actuation magnet dedicated for
generating yaw movement of bottom actuated sub-assembly; and 3) as
a yaw sensing magnet for sensing yaw movement.
[0145] FIG. 15A shows a magnet 1506 and a yoke (e.g. a
ferromagnetic plate such as iron) 1504, where the magnet and yoke
are pulled together by pre-load force (indicated by black double
head arrow) and thus fasten top actuated sub-assembly 210 to bottom
actuated sub-assembly 220. In some examples, magnet 1506 and yoke
1504 are positioned substantially at the center (relative to the Y
axis direction) of the top actuated sub-assembly. Pitch rotation
axis relative to the bottom actuated sub-assembly is demonstrated
by the circular arrow 1508.
[0146] FIG. 15B shows top and bottom actuated sub-assemblies in
isometric view. FIG. 15B illustrates magnet 1510 located at the
internal part of bottom actuated sub-assembly, sensor 1512 and a
coil 1514, which is located at the back of bottom actuated
sub-assembly (in the positive Z direction relative to magnet 1510).
According to one example, a single coil can be used for
actuation.
[0147] As shown in FIG. 15C, yoke 1516, is fastened to the
stationary sub-assembly. Magnet 1510 and yoke 1516 are attracted by
pre-load force to thereby fasten bottom actuated sub-assembly 220
to stationary sub-assembly 230. Coil 1514 is positioned in close
proximity to yaw actuation magnet 1510 (e.g. distance of 100-300
.mu.m). When current is applied in coil 1514, a Lorentz force is
created on yaw magnet 1510 according to d{right arrow over
(F)}=Id{right arrow over (l)}.times.{right arrow over (B)}, where
the Lorentz force is translated into torque around yaw rotation
axis 122 (not shown) as explained above.
[0148] Magnet 1510 moves along the yaw direction as part of the
bottom actuated sub-assembly. In addition of being more compact,
this type of yaw actuation mechanism also provides better
efficiency, as it does not generate force in the opposite direction
to the desired yaw movement.
[0149] As explained above, in some examples top actuated
sub-assembly 210 includes an OPFE holder (or carrier) 302 and
bottom actuated sub-assembly includes a middle moving frame 402.
According to an example, yoke 1504 is attached (e.g. glued) to the
holder and the first magnet-yoke pair (1506-1504) pulls the OPFE
holder to the middle moving frame. Alternatively, the position of
the magnet and yoke can be switched. The stationary sub-assembly
includes a base and the yoke is attached to the based in a manner
that the second magnet-yoke pair (1510-1516) pulls the middle
moving frame to the base. Also, in an example coil 1514 and sensor
1512 are fixed (e.g. glued) to the base.
[0150] According to some examples of the presently disclosed
subject matter yaw magnet 1510, which also serves as yaw sensing
magnet, is made to have an increased detection range. To this end,
magnet 1510 is made to have a single magnetic polarization
direction as indicated by the back arrow extending from the south
pole to the north pole of magnet 1510 shown in FIG. 15D. The
directions of the magnetic field lines are indicated by arrows a-e
in FIG. 15D and in more detail in FIG. 15E, which is a top view of
magnet 1510. As indicated by arrows a-e, as a result of the single
magnetic polarization direction of magnet 1510, the angle of the
magnetic field relative to the magnet surface changes continuously
along the length of magnet. The illustration shows the angle
changing from being substantially perpendicular in the positive
direction at one end, to being in a parallel direction at the
magnet center and to being substantially perpendicular in the
negative direction at the other one. Since the relative changes
(e.g. of magnetic flux) are detectable at each of the points where
change in the direction of the magnetic field occurs, yaw movement
of the magnet relative to sensor 1512 can be detected over an
increased range. The increased detection range of the yaw magnet as
disclosed herein enables to use the same magnet for both actuation
and sensing, eliminating the need for two separate magnets.
[0151] Note that unless stated otherwise terms such as "first" and
"second" as used herein are not meant to imply a particular order
but are only meant to distinguish between two elements or actions
in the sense of "one" and "another".
[0152] While this disclosure has been described in terms of certain
embodiments and generally associated methods, alterations and
permutations of the embodiments and methods will be apparent to
those skilled in the art. The disclosure is to be understood as not
limited by the specific embodiments described herein, but only by
the scope of the appended claims.
[0153] All references mentioned in this specification are herein
incorporated in their entirety by reference into the specification,
to the same extent as if each individual reference was specifically
and individually indicated to be incorporated herein by reference.
In addition, citation or identification of any reference in this
application shall not be construed as an admission that such
reference is available as prior art to the present application.
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