Patent Description:
The present disclosure relates in general to digital cameras, and more particularly to digital cameras with pop-out ("PO") mechanisms and lenses.

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 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.

Multi-aperture digital cameras (or multi-cameras) are standard in today's mobile electronic devices (or in short "mobile devices", e.g. smartphones, tablets, laptops, PDAs, headsets, etc.). In general, a multi-camera includes a Wide camera that acts as the mobile device's main (or "primary") camera, an Ultrawide (UW) camera and an (optional) Tele camera. The Main (or Wide) camera has a Wide camera sensor and a Wide camera field-of-view (FOVw) of about <NUM>-<NUM> degrees (about <NUM> - <NUM> 35eq. FL), the UW camera has as a UW camera sensor and a UW camera field-of-view (FOVuw > FOVw) of about <NUM>-<NUM> degrees (about <NUM> - <NUM> 35eq. FL), and the Tele camera has as a Tele camera sensor and a Tele camera field-of-view (FOVT < FOVw) of about <NUM>-<NUM> degrees (about <NUM> - <NUM> 35eq. A major challenge is the design of Wide cameras that support ever higher image quality (IQ) and still fit into thin mobile devices with device heights of e.g. < <NUM>. For improving the IQ, ever larger image sensors are incorporated in mobile devices. Such large image sensors may have an optical format larger than <NUM>/<NUM>", i.e. they have a sensor diagonal ("SD") of SD><NUM>, e.g. <NUM>/<NUM>" (SD=<NUM>) or even <NUM>/<NUM>" (SD=<NUM>). P-O cameras allow the incorporation of large image sensors while supporting a slim thickness of a mobile device that includes the PO camera. PO cameras are for example described in co-owned international patent application <CIT>.

<FIG> illustrates schematically the definition of various camera entities such as TTL, EFL and BFL. In most miniature lenses which are used in multi-cameras incorporated in mobile devices, the TTL is larger than the EFL, as shown in <FIG> e.g. for a Wide lens.

<FIG> shows an exemplary camera having a lens with a field of view (FOV), an EFL and an image sensor with a sensor width S. For fixed width/height ratios and a (rectangular) image sensor, the (full) image sensor diagonal (SD) is proportional to the sensor width and height. A typical width/height ratio of an image sensor is <NUM>:<NUM>. For example, a <NUM>/<NUM>" sensor has a SD of <NUM>. The diagonal FOV relates to EFL and SD as follows: <MAT>.

This shows that a larger EFL is required for realizing a camera with a larger image sensor, but similar FOV. Incorporating larger image sensors in Wide cameras is desirable, but it requires larger EFL for maintaining the same FOVw, resulting in larger TTL, which is undesirable for integration in a slim mobile device.

<FIG> illustrates schematically a mobile device <NUM> including a known PO camera ("POC") <NUM> in a first state ("collapsed state") when the camera is not in use (or inactive). In the collapsed state, POC <NUM> has a first TTL ("collapsed TTL" or "c-TTL"), as marked. The c-TTL is compatible with the height dimensions of modern mobile devices, i.e. in the collapsed state, PO camera <NUM> does not exceed a height (or thickness) of mobile device <NUM>. The height of mobile device <NUM> may include an elevated area of mobile device <NUM> ("camera bump" or simply "bump") where a multi-camera is included. c -TTL may be in the range of <NUM> - <NUM>.

<FIG> illustrates schematically mobile device <NUM> including POC <NUM> in a second state ("pop-out or "PO" state"). In general, only in the PO state the POC is operational as a camera. In the PO state, POC <NUM> has a second TTL ("TTL") as marked. TTL > c-TTL, so that POC <NUM> exceeds a height of mobile device <NUM>. In other words, in the PO state POC <NUM> protrudes (or "pops out") from mobile device <NUM>. Typically, a mobile device has a thickness ("T") of about T = <NUM> - <NUM>. TTL may be in the range of <NUM> - <NUM>. A POC may protrude from a mobile device <NUM> by about <NUM> - <NUM>.

For switching POC <NUM> from the PO state to the collapsed state, an active actuator such as a stepper motor, a shaped metal alloy (SMA) actuator etc. is required. "Active" means here that an actuation requires an electrical power. Often, for switching POC <NUM> from the collapsed state to the PO state, no active actuator is required, but a passive actuator e.g. based on a spring force is sufficient. In this disclosure, the term "passive" indicates that an actuator and/or actuation does not require electrical power. Recently, "foldable mobile devices" such as "foldable phones" ("FPs") were introduced such as Samsung Galaxy Fold or Samsung Galaxy Flip. FPs can be "folded". When folded, FPs achieve a smaller size, what is desired. When unfolded, FPs provide a large screen area for a primary screen, what is desired as well. In general, when folded, the primary screen of a FP is not active.

POCs including a SMA actuator are described for example in co-owned international patent application <CIT>. Often, a SMA actuator uses SMA wires. SMA wires are beneficial for use in mobile devices, as they are inexpensive, light-weight, compact and can be used for low-power, low-noise, compact actuators. In general, SMA wires are operational under load for e.g. twenty-five thousand (<NUM>,<NUM>) cycles, which is unbeneficial as operation over hundred thousand (<NUM>,<NUM>) cycles may be mandatory when used in a mobile device.

It would be beneficial to have Wide camera lens designs that support PO Wide cameras including large image sensors such as <NUM>/<NUM>" or larger, i.e. having a SD ≥ <NUM>.

It would be beneficial to have a fully passive POC included in a mobile device, i.e. a relatively slim camera that still provides a large zoom effect or uses a large image sensor, and which does not require active actuation when switching from a PO state to a collapse state and vice versa. Such a fully passive POC is disclosed herein.

It would be beneficial to have a SMA actuator that is operational for a relatively large number of cycles (e.g. up to <NUM>,<NUM> cycles) and for use in a mobile device. Such a SMA actuator camera is disclosed herein.

<CIT> discloses cameras with optical image stabilization function capable of performing macro photography with two lens groups which can be configured in a pop-out state and in a collapsed state. In the collapsed state of the lens, the total track length is smaller than <NUM> times the minimal effective focal length.

According to the invention, a lens system for a compact digital camera according to claim <NUM> is provided. Further aspects of the invention are defined by the dependent claims.

Non-limiting examples of examples disclosed herein 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 are generally labeled with a same numeral in all the figures in which they appear. If identical elements are shown but numbered in only one figure, it is assumed that they have the same number in all figures in which they appear. The drawings and descriptions are meant to illuminate and clarify examples disclosed herein and should not be considered limiting in any way. In the drawings:.

<FIG> shows a known art example of a "<NUM>-group" (or "<NUM>") pop-out ("PO") optical lens system <NUM> that comprises a PO lens <NUM> and an image sensor <NUM>. PO optical lens system <NUM> is shown in a PO or extended state (and focused to infinity). PO lens <NUM> is divided into two lens groups which are separated by a big gap (BG), a first, object-sided lens group ("G1") and a second, sensor-sided lens group ("G2"). The thickness of G1 is indicated by TG1. Lens <NUM> includes a plurality of N lens elements Li (wherein "i" is an integer between <NUM> and N and wherein N may be for example between <NUM> and <NUM>). L1 is the lens element closest to the object side and LN is the lens element closest to the image side, i.e. the side where the image sensor is located. This order holds for all lenses and lens elements disclosed herein. Each lens element Li comprises a respective front surface S2i-<NUM> (the index "2i-<NUM>" being the number of the front surface) and a respective rear surface S2i (the index "2i" being the number of the rear surface). This numbering convention is used throughout the description. Alternatively, as done throughout this description, lens surfaces are marked as "Sk", with k running from <NUM> to 2N. The front surface and the rear surface may be in some cases aspherical. This is however not limiting.

As used herein the term "front surface" of each lens element refers to the surface of a lens element located closer to the entrance of the camera (camera object side) and the term "rear surface" refers to the surface of a lens element located closer to the image sensor (camera image side).

Each lens group includes one or more lens elements Li. G1 may include ≥ <NUM> elements and G2 may include <NUM>-<NUM> elements. G2 may act as a field lens as known in the art.

<FIG> shows <NUM> PO optical lens system <NUM> in a collapsed state. Big gap BG is collapsed to a collapsed BG (marked "c-BG"), i.e. a distance between G1 and G2 is reduced, resulting in a collapsed TTL ("c-TTL"). c-BG may be in the range <NUM>-<NUM>. Only BG changes. No other distances in PO optical lens system <NUM>, such as a BFL or distances between lens elements included in G1 and G2 respectively, change.

<FIG> shows another example of a <NUM> PO optical lens system <NUM> that comprises a PO lens <NUM> having a lens thickness TLens and an image sensor <NUM> disclosed herein in a PO state. PO lens <NUM> has a lens optical axis, as shown. <NUM> PO optical lens system <NUM> is shown in a PO or extended state (and focused to infinity). Lens <NUM> includes a plurality of N lens elements. A BFL is shown.

<FIG> shows <NUM> PO optical lens system <NUM> in a collapsed state. BFL is collapsed to a collapsed BFL (marked "c-BFL"), i.e. a distance between lens <NUM> and image sensor <NUM> is reduced, resulting in a collapsed TTL ("c-TTL"). A fundamental lower limit for c-TTL is given by the thickness of lens <NUM> ("TLens"), i.e. c-TTL > TLens. In fact, c-TTL = TLens + c-BFL, wherein, c-BFL=<NUM>-<NUM> or more. This means that c-TTL = TLens + <NUM> - TLens + <NUM> or more.

<NUM> PO optical lens system <NUM> and is operational to be used in a PO camera. The resulting POC is operational as a camera only in the PO state. In the collapsed state, the POC is not operational as a camera, i.e. it is inactive.

<NUM> PO optical lens system <NUM> is a "<NUM>-group" (or "<NUM>") PO optical lens system, i.e. lens <NUM> moves as one unit, meaning that distances between lens elements included in lens <NUM> do not change when switching from the PO state to the collapsed state, but only the BFL changes. <NUM> PO optical lens system <NUM> and <NUM> PO optical lens system <NUM> can (or are operational to) be included in a POC. For performing optical image stabilization (OIS), the POC may use several methods known in the art. Such methods may be "lens shift OIS", wherein the lens is moved relative to the image sensor and a camera hosting mobile device for OIS, or "sensor shift OIS", wherein the image sensor is moved relative to the lens and to a camera hosting mobile device for OIS.

All PO optical lens systems disclosed herein can be used in the POC examples described in co-owned PCT patent application <CIT>.

All PO optical lens systems disclosed below are shown in a PO state, where a POC including the optical lens system is operational.

In a collapsed state, all <NUM> PO optical lens system examples have a c-BG of <NUM>-<NUM>. A small c-BG is beneficial for achieving a slim camera module that can be integrated in a slim mobile device such as a smartphone. A cTTL may be in the range between <NUM> to <NUM>. In a collapsed state, all <NUM> PO optical lens system examples have a c-BFL of <NUM>-<NUM>. A small c-BFL is beneficial for achieving a slim camera module. A cTTL may be in the range between <NUM> to <NUM>. To clarify, all lens systems disclosed herein may beneficially be included or incorporated in mobile devices such as smartphones.

<FIG> shows an example of a <NUM> PO optical lens system disclosed herein not according to the claims and numbered <NUM>. Lens system <NUM> comprises a PO lens <NUM> divided into two lens groups G1 and G2 and having a lens optical axis <NUM>, an image sensor <NUM> and, optionally, an optical element <NUM>. Optical element <NUM> may be for example infra-red (IR) filter, and/or a glass image sensor dust cover. Image sensor <NUM> may have a SD of <NUM>. G1 includes <NUM> lens elements (L<NUM>-L<NUM>) and G2 includes <NUM> lens elements (L<NUM>-L<NUM>). Optical rays pass through lens <NUM> and form an image on image sensor <NUM>. <FIG> shows <NUM> fields with <NUM> rays for each.

Detailed optical data and surface data for PO lens <NUM> are given in Tables <NUM>-<NUM>. Table <NUM> provides surface types and Table <NUM> provides aspheric coefficients. The surface types are:.

where {z, r} are the standard cylindrical polar coordinates, c is the paraxial curvature of the surface, k is the conic parameter, rnorm is generally one half of the surface's clear aperture (CA), and An are the aspheric coefficients shown in lens data tables. The Z axis is positive towards the image side. Values for CA are given as a clear aperture radius, i.e. D/<NUM>. The reference wavelength is <NUM>. Units are in mm except for refractive index ("Index") and Abbe #. Each lens element Li has a respective focal length fi, given in Table <NUM>. The FOV is given as half FOV (HFOV).

The power sequence for lens element from L<NUM> to L<NUM> is as follows: +-+--+-+- (plus-minus-plus-minus-minus-plus-minus-plus-minus), i.e. PO lens <NUM> includes four positive lens elements and five negative lens elements. Both L<NUM> and L<NUM> have large maximum SAG of <NUM> and <NUM> respectively, as indicated by "Max_SAGL8" and "Max_SAGL9" respectively.

<FIG> shows another example of a <NUM> PO optical lens system disclosed herein not according to the claims and numbered <NUM>. Lens system <NUM> comprises a PO lens <NUM> divided into two lens groups G1 and G2 and having a lens optical axis <NUM>, an image sensor <NUM> and, optionally, an optical element <NUM>. Image sensor <NUM> may have a SD of <NUM>. G1 includes <NUM> lens elements (L<NUM>-L<NUM>) and G2 includes <NUM> lens element (L<NUM>). Detailed optical data and surface data for PO lens <NUM> are given in Tables <NUM>-<NUM>. Table <NUM> provides surface types and Table <NUM> provides aspheric coefficients.

<FIG> shows an example of a <NUM> PO optical lens system disclosed herein not according to the claims and numbered <NUM>. Lens system <NUM> comprises a PO lens <NUM> having a lens optical axis <NUM>, an image sensor <NUM> and, optionally, an optical element <NUM>. Image sensor <NUM> may have a SD of <NUM>. PO lens <NUM> includes <NUM> lens elements (L<NUM>-L<NUM>). Optical rays pass through lens <NUM> and form an image on image sensor <NUM>. Detailed optical data and surface data for PO lens <NUM> are given in Tables <NUM>-<NUM>. Table <NUM> provides surface types and Table <NUM> provides aspheric coefficients.

<FIG> shows an example of a <NUM> PO optical lens system disclosed herein according to the claims and numbered <NUM>. Lens system <NUM> comprises a PO lens <NUM> having a lens optical axis <NUM>, an image sensor <NUM> and, optionally, an optical element <NUM>. Image sensor <NUM> may have a SD of <NUM>. PO lens <NUM> includes <NUM> lens elements (L<NUM>-L<NUM>). Optical rays pass through lens <NUM> and form an image on image sensor <NUM>. Detailed optical data and surface data for PO lens <NUM> are given in Tables <NUM>-<NUM>. Table <NUM> provides surface types and Table <NUM> provides aspheric coefficients.

As of L<NUM>'s lens shape, not the entire BFL can be collapsed, but only a BG expanding from a closest point of L<NUM> to image sensor <NUM> and to optical element <NUM> respectively.

Table <NUM> shows the values and ranges of optical lens systems <NUM>, <NUM>, <NUM>, <NUM> and <NUM> disclosed herein.

<FIG> shows exemplarily a foldable phone ("FP") <NUM> including an inner passive POC <NUM> as disclosed herein. "Inner" means here that a FOV <NUM> of camera <NUM> is located at a same side of FP <NUM> as its "primary screen". The primary screen is a largest screen (i.e. having a largest screen area) included in FP <NUM>. FP <NUM> includes a hinge axis <NUM> that connects a first wing <NUM> with a second wing <NUM> and which is operational to allow unfolding and folding FP <NUM>. Hinge axis <NUM> is oriented perpendicular to the x-y plane. First wing <NUM> includes a first outer (or "world-facing") side <NUM> and a first inner (or "user-facing") side <NUM>. Second wing <NUM> includes a second outer side <NUM> and a second inner side <NUM>. In general, the primary screen of FP <NUM> expands over both first inner side <NUM> and second inner side <NUM>. When FP <NUM> is unfolded, the primary screen can be used in its entirety and inner passive POC <NUM> is operational (or "active") as user-facing (or "selfie") camera. In some examples, first outer side <NUM> and/or second outer side <NUM> also include a screen. When FP <NUM> is folded, an aperture of inner passive POC <NUM> is covered by second wing <NUM>. Inner passive POC <NUM> includes a passive PO actuator (<FIG>), a PO lens <NUM> having lens optical axis ("OA") a lens thickness TL and an image sensor <NUM>. Inner passive POC <NUM> is included in, and surrounded by a camera module housing (or simply "camera housing") <NUM>.

<FIG> shows FP <NUM> in a partly unfolded state, in which passive POC <NUM> is in a PO state. In the PO state, inner passive POC <NUM> has a TTL and is active as a camera, i.e. PO lens <NUM> is operational to image a crisp (or clear) image of a scene onto image sensor <NUM>. In the PO state, a height of camera housing <NUM> ("HC") is defined by TTL and a mechanical "penalty" ("p"), HC = TTL + p, wherein p may be in the range of <NUM> - <NUM>. A low HC is beneficial for use in slim mobile devices such as smartphones. Here and in the following, HC, TTL and p are measured along the z-axis.

<FIG> shows the FP <NUM> in a folded state. In the folded state, inner passive POC <NUM> is in a collapsed state. In the collapsed state, the passive POC has a c-TTL < TTL and is not active as a camera. An unfolding movement to switch between the folded state (<FIG>) and the unfolded state (<FIG>) is indicated by arrow <NUM>. A folding movement to switch between the partly unfolded state (<FIG>) and the folded state (<FIG>) is indicated by arrow <NUM>. The unfolding and folding movements are in general performed manually by a user. A height ("H") of each of first wing <NUM> and second wing <NUM> is shown. First wing <NUM> has a regular region having a height ("H") and a bump region having an elevated height H + B, wherein "B" is a bump height. The bump region extrudes from first inner side <NUM>. Inner passive POC <NUM> is integrated in the bump region, and inner passive POC <NUM> receives light from a scene facing first inner side <NUM>. In the collapsed state, camera housing <NUM> has a collapsed height ("c-HC") < HC which is defined by c-HC = c-TTL + p. c-HC ≤ H, so that in the collapsed state no camera bump is present. In other examples, in the collapsed state a reduced camera bump may be present. "Reduced" means here that a camera bump has a lower B compared to the PO state. Here and in the following, H, B, c-HC and c-TTL are measured along the z-axis.

<FIG> shows a zoom-in section <NUM> of FP <NUM> in a folded state and with inner passive POC <NUM> in a collapsed state. Section <NUM> shows a passive PO actuator <NUM> as disclosed herein. Passive PO actuator <NUM> includes a spring <NUM>. At an upper end, spring <NUM> is fixedly attached to first outer side <NUM>, or more general, to a component included in first wing <NUM> which does not move relative to first wing <NUM>. At a lower end, spring <NUM> is fixedly attached to a PO lens barrel including PO lens <NUM>. In the collapsed state, spring <NUM> stores a kinetic energy and is operational to provide a spring force as indicated by arrow <NUM>, i.e. spring <NUM> is loaded. When a user unfolds FP <NUM>, spring <NUM> relaxes and the spring force actuates (or "pops out") inner passive POC <NUM>, i.e. inner passive POC <NUM> is switched to the PO state. When a user folds FP <NUM>, spring <NUM> is compressed and loaded, so that inner passive POC <NUM> is switched to the collapsed state. We note that when FP <NUM> is folded by a user, simultaneously passive POC <NUM> is switched from a PO state to a collapsed state. When FP <NUM> is unfolded by a user, simultaneously passive POC <NUM> is switched from a collapsed state to a PO state. As desired for mobile devices such as FPs, no active actuation is required.

In some examples, a mechanical spring may be used, as shown here. In other examples, a magnetic spring may be used. A magnetic spring may include a magnet and a yoke, or alternatively, two magnets. Such magnetic springs are for example described in co-owned international patent applications No. <CIT>and No. <CIT>.

<FIG> shows exemplarily a FP <NUM> including an outer passive POC <NUM> as disclosed herein. "Outer" means here that a FOV <NUM> of passive POC <NUM> is located at an opposite side of FP <NUM>'s primary screen. FP <NUM> includes all components as described in <FIG>, except of a different passive POC. Both in FP <NUM>'s folded state and in its unfolded state, an aperture of outer passive POC <NUM>'s FOV <NUM> receives light from a scene. Outer passive POC <NUM> includes a passive PO actuator (<FIG>), a PO lens <NUM> and an image sensor <NUM>. Outer passive POC <NUM> is included in a camera housing <NUM>.

<FIG> shows FP <NUM> in a partly unfolded state, with outer passive POC <NUM> in a PO state. The bump region extrudes from first outer side <NUM>. Outer passive POC <NUM> is integrated in the bump region and receives light from a scene facing first outer side <NUM>.

<FIG> shows the FP <NUM> in a folded state, with outer passive POC in a collapsed state.

<FIG> shows a zoom-in section <NUM> of FP <NUM> in a folded state and with outer passive POC <NUM> in a collapsed state. Section <NUM> shows a passive PO actuator <NUM> as disclosed herein and including a magnetic spring <NUM>. Magnetic spring <NUM> includes a first magnet <NUM> fixedly attached to a PO lens barrel including PO lens <NUM> and a second magnet <NUM> fixedly attached to second wing <NUM>. First magnet <NUM> and second magnet <NUM> are selected and oriented so that they attract each other. In the collapsed state, first magnet <NUM> and second magnet <NUM> are relatively close to each other, so that a magnetic energy is stored and magnetic spring <NUM> is operational to provide a magnetic spring force as indicated by arrow <NUM>. The magnetic spring force collapses outer passive POC <NUM>. When a user unfolds FP <NUM>, magnetic spring <NUM> relaxes and no magnetic spring force is provided. Another spring included in outer passive POC <NUM> may provide a spring force to pop out outer passive POC <NUM>, i.e. outer passive POC <NUM> is switched to the PO state. First magnet <NUM> and second magnet <NUM> are relatively distant from each other. When a user folds FP <NUM>, first magnet <NUM> and second magnet <NUM> approach each other again, and outer passive POC <NUM> is switched to the collapsed state. We note that when FP <NUM> is folded by a user, simultaneously outer passive POC <NUM> is switched from the PO state to the collapsed state. When FP <NUM> is unfolded by a user, simultaneously outer passive POC <NUM> is switched from the collapsed state to the PO state. As desired for mobile devices such as FPs, no active actuation is required.

<FIG> show exemplarily a FP <NUM> including an outer passive POC <NUM> as disclosed herein. FP <NUM> includes all components as described in <FIG>, except of a different passive POC. Outer passive POC <NUM> includes a passive PO actuator <NUM> as disclosed herein, a PO lens <NUM>, an image sensor <NUM> and is included in a camera housing <NUM>.

<FIG> shows FP <NUM> in a partly unfolded state, with passive POC <NUM> in a PO state.

<FIG> shows the FP <NUM> in a folded state, with passive POC in a collapsed state. The bump region extrudes from first outer side <NUM>. Outer passive POC <NUM> is integrated in the bump region and receives light from a scene facing first outer side <NUM>. PO actuator <NUM> includes a plurality of O gear wheels (here, O=<NUM>), a first gear wheel <NUM>, a second gear wheel <NUM> and a third gear wheel <NUM>. PO actuator <NUM> is located at, or in proximity of, hinge axis <NUM>. For example, PO actuator <NUM> may be located at a distance of up to <NUM> from hinge axis <NUM>. In fact, also outer passive POC <NUM> is located relatively close to hinge axis <NUM>. For example, POC <NUM> may be located at a distance of up to <NUM> from hinge axis <NUM>. PO actuator <NUM> uses a movement such as an unfolding movement indicated by arrow <NUM> or a folding movement indicated by arrow <NUM> to switch outer passive POC <NUM> from the PO state to the collapsed state as indicated by arrow <NUM>, and vice versa. , PO actuator <NUM> translates a rotational unfolding or folding movement of first wing <NUM> and second wing <NUM> around hinge axis <NUM> into a linear movement along the z-axis of a PO lens barrel including PO lens <NUM> and relative to image sensor <NUM>. We note that when FP <NUM> is folded by a user, simultaneously outer passive POC <NUM> is switched from a PO state to a collapsed state. When FP <NUM> is unfolded by a user, simultaneously outer passive POC <NUM> is switched from a collapsed state to a PO state. As desired for mobile devices such as FPs, no active actuation is required.

<FIG> show exemplarily a FP <NUM> including an outer passive POC <NUM> as disclosed herein. <FIG> shows FP <NUM> in a partly unfolded state, with outer passive POC <NUM> in a PO state. FP <NUM> includes all components as described in <FIG>, except of a different passive POC. Outer passive POC <NUM> receives light from a scene facing first outer side <NUM>. In the PO state, outer passive POC <NUM> is operational as a folded camera as known in the art. Outer passive POC <NUM> includes a passive PO actuator (not shown), a lens <NUM>, a mirror <NUM>, an image sensor <NUM> and is included in a camera housing <NUM>. Outer passive POC <NUM> is operational to receive light along a first optical path ("OP1") parallel to the z-axis. An OA of lens <NUM> is parallel to OP1. In the PO state, mirror <NUM> is oriented at an angle of about <NUM> degrees with respect to the z-axis, so that reflected light propagates along a second optical path ("OP2") parallel to the z-axis and towards image sensor <NUM>. Lens <NUM> is located at an object side of mirror <NUM>, what provides a relatively low f/# for a given camera height, as beneficial for use in mobile devices such as FPs. Such cameras are for example described in co-owned international patent application No. <CIT>. In the PO state, camera housing <NUM> has a first elevated ("module") region including PO lens <NUM> and mirror <NUM>, as well as a second ("shoulder") region including image sensor <NUM>. The module region has a minimum module height ("MHM") defined by a sum of TL, a height of mirror <NUM>, and an air gap of about <NUM> - <NUM> between PO lens <NUM> and mirror <NUM>. A height of the module region of camera housing <NUM> ("HM") measured along the z-axis is defined by MHM and a mechanical "penalty" ("p"), HM = MHM + p, wherein p may be in the range of <NUM> - <NUM>. The shoulder region has a minimum shoulder height ("MHS") < MHM and which is defined by a height of image sensor <NUM> measured along the z-axis. A height of the shoulder region of camera housing <NUM> ("HS") measured along the z-axis is defined by MHS and a mechanical "penalty" ("p"), HS = MHS + p, wherein p may be in the range of <NUM> - <NUM>. A low HM and a low HS are beneficial for use in slim mobile devices such as smartphones. As HS < HM, the shoulder region can be integrated into the regular region of height H. Only the module region is integrated in the bump region. In other words, outer passive POC <NUM> is only partially integrated in the bump region, what is beneficial for achieving a relatively small bump region. Here and in the following, a height, an air gap, MHM, HM, MHS, HS and p are measured along the z-axis.

<FIG> shows the FP <NUM> in a folded state, with outer passive POC <NUM> in a collapsed state. For switching from the PO state to the collapsed state, PO lens <NUM> is linearly moved towards second wing <NUM>. Mirror <NUM> is rotationally moved by about <NUM> degrees around an axis perpendicular to OP1 and OP2 so that it forms an angle of about <NUM> degrees with the y-axis, and in addition it is linearly moved towards second wing <NUM>. "About" means here for example a variation of ±<NUM> degrees or ±<NUM> degrees. The respective movements are performed so that MHM is collapsed to a c-MHM < MHM, and HM is collapsed to a c-HM < HM, given by c-HM = c-MHM + p. c-HM ≤ H, so that in the collapsed state no camera bump is required. MHS does not change. For providing an actuation of the respective movements of PO lens <NUM> and mirror <NUM>, outer passive POC <NUM> may include a passive PO actuator such as passive PO actuator <NUM> (<FIG>) including a magnetic spring or it may include a passive PO actuator such as passive PO actuator <NUM> (<FIG>) including a plurality of gear wheels.

<FIG> shows a SMA actuator <NUM> as disclosed herein. SMA actuator <NUM> is operational for (or "over") a relatively large number of cycles (for an example see below) and for use in a camera of a mobile device such as a smartphone. SMA actuator <NUM> includes a moving element <NUM> which is operational to move relative to a mobile device including moving element <NUM>, for example for switching a POC from a PO state and a collapsed state and vice versa, for focusing a lens or for movements of a lens or an image sensor for optical image stabilization (OIS). Moving element <NUM> includes a plurality of P rails <NUM> (here, P=<NUM>), a first rail <NUM>, a second rail <NUM>, a third rail <NUM> and a fourth rail <NUM>. SMA actuator <NUM> includes a plurality of P SMA wires <NUM> (here, P=<NUM>), a first SMA wire <NUM>, a second SMA wire <NUM>, a third SMA wire <NUM> and a fourth SMA wire <NUM>. Each of the P SMA wires <NUM> is located in and guided by one of the P rails <NUM>. A preload force is applied between P SMA wires <NUM> and P rails <NUM>, so that P SMA wires <NUM> do not detach (or "derail") from moving element <NUM>. SMA actuator <NUM> also includes a first plurality of P crimps <NUM> and a second plurality of P crimps <NUM>. overall, SMA actuator <NUM> includes 2P crimps. Each of the crimps included in first plurality of P crimps <NUM> and second plurality of P crimps <NUM> is fixedly attached to one end of each SMA wire included in P SMA wires <NUM>, as shown. The crimps provide a mechanical and electrical connection. In other examples, a plurality of P rails and P SMA wires respectively may include P = <NUM> - <NUM>.

A movement of moving element <NUM> may be a rotational movement along a rotation axis <NUM> parallel to the z-axis. Rotation axis <NUM> may be located at a center of moving element <NUM>. In other examples, a movement of moving element <NUM> may be a linear movement in the x-y plane, as indicated by arrow <NUM>. For actuating such linear or rotational movement, SMA actuator <NUM> is operational to drive a current through one of P SMA wires <NUM>. , during actuation, only one of P SMA wires <NUM> is operated. In other words, SMA actuator <NUM> operates P SMA wires <NUM> consecutively. For example, during a first period of time, only first SMA wire <NUM> is operated, during a second period of time, only second SMA wire <NUM> is operated, during a third period of time, only third SMA wire <NUM> is operated and during a fourth period of time, only fourth SMA wire <NUM> is operated. This can be beneficial to extend (or prolong) a number of cycles SMA actuator <NUM> is operational. For example, a single SMA wire may be operational under load for M cycles, but a specification of a SMA actuator may require operation over PxM cycles. By consecutively operating P SMA wires as detailed above, the specification of PxM cycles can be satisfied. For example, a single SMA wire such as first SMA wire <NUM> may be operational under load for M = twenty-five thousand (<NUM>,<NUM>) cycles, but a specification of SMA actuator <NUM> may require operation over 4xM = hundred thousand (<NUM>,<NUM>) cycles. By consecutively operating four SMA wires <NUM> as detailed above, the specification of hundred thousand (<NUM>,<NUM>) cycles can be satisfied. In this example, a relatively large number of cycles is hundred thousand (<NUM>,<NUM>) cycles. In other examples, a relatively large number of cycles may be in the range of five thousand (<NUM>,<NUM>) cycles to five hundred thousand (<NUM>,<NUM>) cycles.

While this disclosure has been described in terms of certain examples and generally associated methods, alterations and permutations of the examples and methods will be apparent to those skilled in the art within the scope of the claims.

The disclosure is to be understood as not limited by the specific examples described herein, but only by the scope of the appended claims.

It is appreciated that certain features of the presently disclosed subject matter, which are, for clarity, described in the context of separate examples, may also be provided in combination in a single example, within the scope of the claims. Conversely, various features of the presently disclosed subject matter, which are, for brevity, described in the context of a single example, may also be provided separately or in any suitable sub-combinations, within the scope of the claims.

Claim 1:
A lens system <NUM> for a compact digital camera, the lens system having a pop-out state and a collapsed state and comprising:
an image sensor <NUM> having a sensor diagonal SD; and
a lens with N lens elements L1-LN arranged along a lens optical axis OA starting with L1 from an object side towards an image side, each lens element Li having a respective clear aperture diameter DALi wherein <NUM>≤ i ≤ N, and having in the pop-out state a field of view FOV and a f number (f/#), a lens thickness TLens, a back focal length BFL, an effective focal length EFL, and a total track length TTL <<NUM>, wherein the lens system is configured to switch from a pop-out state to a collapsed state and vice versa by collapsing BFL to a collapsed back focal length c-BFL, wherein BFL > <NUM> x TTL, wherein a ratio c-TTL/SD < <NUM>, wherein c-TTL represents a collapsed total track length, and wherein f/#:<NUM>, characterized in that SD≥<NUM>.