Patent Description:
The presently disclosed subject matter is related in general to the field of digital cameras and in particular to folded lenses in such cameras.

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:.

Multi-aperture cameras (or "multi-cameras", of which a "dual-cameras" having two cameras is an example) are becoming the standard choice of portable electronic mobile device (e.g. smartphones, tablets, etc.) makers. A multi-camera setup usually comprises a wide field-of-view (or "angle") FOVW camera ("Wide" camera or "W" camera), and at least one additional camera, either with the same FOV (e.g. a depth auxiliary camera), with a narrower (than FOVW) FOV (Telephoto or "Tele" camera with FOVT), or with an ultra-wide field of view FOVUW (wider than FOVW, "UW" camera).

<FIG> illustrate a known digital folded camera <NUM>. Camera <NUM> comprises an optical path folding element (OPFE) <NUM> e.g. a prism or mirror, a lens <NUM> with a plurality of lens elements (not visible in this representation, but visible e.g. in <FIG>) and an image sensor <NUM>. The lens elements may be (as in <FIG>) axial symmetric along an optical axis <NUM>. In other embodiments, the lens elements may not be axial symmetric. For example, lens elements may be cut (diced, sliced) into a non-circular shape (not shown).

At least some of the lens elements may be included in a "barrel" <NUM>. The barrel may have a longitudinal symmetry along optical axis <NUM>. In <FIG>, the cross-section of this barrel is circular. This is however not mandatory and other shapes can be used, e.g. for hosting cut lens elements.

The path of the optical rays from an object (not shown) to image sensor <NUM> defines an optical path (see optical paths <NUM> and <NUM>, which represent portions of the optical path). OPFE folds the optical path from a first optical path <NUM> to a second optical path <NUM>, the latter being substantially parallel to optical axis <NUM>.

In particular, in some examples, OPFE <NUM> is inclined at substantially <NUM> degrees with respect to optical axis <NUM>. In <FIG>, OPFE <NUM> is also inclined at substantially <NUM> degrees with respect to optical path <NUM>.

In some known examples, image sensor <NUM> lies in a X-Y plane substantially perpendicular to optical axis <NUM>. This is however not limiting, and image sensor <NUM> can have a different orientation. For example, and as described in international published patent application <CIT>, image sensor <NUM> may lie in the XZ plane. In this case, an additional OPFE can be used to reflect the optical rays towards image sensor <NUM>.

Two cameras, for example a Wide camera <NUM> and a regular UW camera <NUM> may be included in a digital camera <NUM> (also referred to as dual-camera). A possible configuration is shown in <FIG>. UW camera <NUM> may include an aperture <NUM> (indicating the object side of the camera) and an optical lens system <NUM> (or "Wide lens module") with a symmetry (and optical) axis <NUM> in the Y direction, as well as a UW image sensor <NUM>. The UW camera comprises a UW lens system configured to provide a UW image. As already indicated, the UW camera has a field of view FOVuw larger than FOVw. For example, FOVuw may be <NUM>-<NUM> degrees and FOVW may be <NUM>-<NUM> deg. Notably, in other examples, a plurality of Wide cameras and/or a plurality of Tele cameras can be incorporated and operative in a single digital camera. The FOVT of a Tele camera may be for example <NUM>-<NUM> degrees.

A "Macro-photography" mode is becoming a popular differentiator for smartphone cameras. "Macro-photography" refers to photographing objects close to the camera, so that an image recorded on the image sensor is nearly as large as the actual object photographed. The ratio of image size to object size is the object-to-image magnification M, defined by: <MAT> where v is a lens-image distance defined by the distance of the <NUM>nd (or "rear") principal plane of the lens and the image, and u is an object-lens distance defined by the distance of the object to the <NUM>st (or "front") principal plane of the lens. The minus sign is generally not mentioned explicitly.

In the context of digital single-lens reflex (DSLR) cameras, a Macro image is defined by having a M of about <NUM>:<NUM> or larger, e.g. <NUM>:<NUM>. In the context of smartphones, "Macro image". may refer to images with M of about <NUM>:<NUM> or even <NUM>:<NUM>. First smartphone models have entered the consumer market that provide Macro-photography capabilities, usually by enabling very close focusing with a UW camera, which has a relatively short EFL (e.g. <NUM>).

A UW camera can focus to the close range required for Macro photography (e.g., <NUM> to <NUM>), but its spatial resolution is poor since its focal length is small and its FOV is large. For example, consider a UW camera with <NUM> focal length. When focused to an object at <NUM> (lens-object distance), the UW camera will have approximately M=<NUM>:<NUM>. This according to thin lens equation <MAT> with EFL =<NUM>, v = <NUM> and u=<NUM>. Even when focused to as close as <NUM>, the M of the UW camera will be approximately <NUM>:<NUM>. Capturing objects in Macro images from these short object-lens distances of e.g. u=<NUM> or less is very challenging for a user. For example, it may render framing of the image very difficult, it may prohibit taking images of popular Macro objects such as living subjects (e.g. insects), and it may introduce shadows and obscure the lighting in the scene. Additionally, an UW camera has a relatively large depth of field (DoF), even for Macro images. The relatively large DoF corresponds to a low degree of optical Bokeh, which is a highly popular effect in Macro photography.

<CIT> discloses a folded lens system that may include multiple lenses with refractive power and a light path folding element. Light entering the camera through lens(es) on a first optical path or axis is refracted to the folding element, which changes direction of the light onto a second optical path or axis with lens(es) that refract the light to form an image plane at a photosensor. At least one of the object side and image side surfaces of at least one of the lens elements may be aspheric. Total track length (TTL) of the lens system may be <NUM> or less. The lens system may be configured so that the telephoto ration |TTL/f| is greater than <NUM>. Materials, radii of curvature, shapes, sizes, spacing, and aspheric coefficients of the optical elements may be selected to achieve quality optical performance and high image resolution in a small form factor camera.

<CIT> discloses a wide-angle lens for imaging objects disposed away from the optical axis towards the periphery of the field of view.

<CIT> discloses a lens system for a folding reflex camera. The system includes: (a) a first group on the object side of the system's stop which (i) has a positive dioptric power, (ii) includes an aspheric surface, and (iii) has a concave surface adjacent to the stop; and (b) a second group on the image side of the stop consisting of either a single positive component or the combination of a single positive component and one or more focusing elements. The system includes at least two elements made of materials differing in dispersive powers where at least one of the elements is of plastic. The system can comprise just two plastic elements and even with such a simple configuration achieves excellent optical performance including a relatively flat field, relatively low distortion, and at least partial correction for lateral chromatic aberration.

It would be beneficial to have a Macro camera in mobile devices that captures Macro images from a larger lens-object distance (e.g. <NUM>-<NUM>) with larger object to image magnification (e.g. <NUM>:<NUM> - <NUM>:<NUM>), and which has a high degree of optical Bokeh.

In various embodiments, there are provided folded digital cameras as defined by claim <NUM>. Further details are defined by the dependent claims.

Non-limiting examples of embodiments disclosed herein are described below with reference to figures attached hereto that are listed following this paragraph. The drawings and descriptions are meant to illuminate and clarify embodiments disclosed herein, and should not be considered limiting in any way.

In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding. However, it will be understood by those skilled in the art that the presently disclosed subject matter may be practiced without these specific details. In other instances, well-known methods have not been described in detail so as not to obscure the presently disclosed subject matter.

<FIG> illustrate various lens systems disclosed herein. All lens systems shown in <FIG> can be included in a folded camera such as shown in <FIG>.

<FIG> shows schematically an optical lens system disclosed herein and numbered <NUM>. Lens system <NUM> comprises a lens <NUM>, an optical element <NUM> and an image sensor <NUM>. System <NUM> is shown with ray tracing. Optical element <NUM> may be for example an infra-red (IR) filter, and/or a glass image sensor dust cover. Optical rays (after their reflection by prism <NUM>) pass through lens <NUM> and form an image on image sensor <NUM>. <FIG> shows <NUM> fields with <NUM> rays for each: the upper marginal-ray, the lower marginal-ray and the chief-ray. In the example of <FIG>, the optical rays pass through optical element <NUM> before impinging on image sensor <NUM>. This is however not limiting, and in some examples, optical element <NUM> is not present. That is, the optical element may be optional in some designs.

Lens <NUM> includes a plurality of N lens elements Li where "i" is an integer between <NUM> and N. In lens system <NUM>, N is equal to six. This is however not limiting and a different number of lens elements can be used. According to the claimed invention, N is equal to or greater than <NUM>. For example, N can be equal to <NUM>, <NUM>, <NUM>, <NUM> or <NUM>. L<NUM> is the lens element closest to the object (prism) 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. Lens elements Li can be used e.g. as lens elements of a camera similar to camera <NUM>. The N lens elements are axial symmetric along an optical (lens) axis <NUM>. 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 can 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).

As explained below, a clear height value CH(Sk) and a clear aperture value CA(Sk) can be defined for each surface Sk (for <NUM> ≤ k ≤ 2N. CA(Sk) and CH(Sk) define optical properties of each surface Sk of each lens element. The CH term is defined with reference to <FIG> and the CA term is defined with reference to <FIG>.

In addition a height HLi (for <NUM> ≤ i ≤ N) is defined for each lens element Li. HLi corresponds, for each lens element Li, to the maximal height of lens element Li measured along an axis perpendicular to the optical axis of the lens elements. For a given lens element, the respective HLi is greater than, or equal to the CH and the CA of the front and rear surfaces of this given lens element. Typically, for an axial symmetric lens element, HLi is the diameter of lens element Li as seen in <FIG>. Typically, for an axial symmetric lens element, HLi = max{CA(S2i-<NUM>), CA(S2i)} + a mechanical part size. In general, in lens design the mechanical part size is defined as not contributing to the optical properties of the lens. Consequently, one defines two heights of a lens element Li, an optical height Hopt,i (corresponding to the CA value) of an optically active area <NUM> and a geometrical height of the lens HLi of an entire lens area <NUM> which covers an optically active and an optically inactive area. The mechanical part and its properties are defined below. The mechanical part size contribution to HLi is typically <NUM>-<NUM>.

In lens system <NUM>, some of the surfaces of the lens elements are represented as convex, and some are represented as concave. The representation of <FIG> is however not limiting, and a different combination of convex and/or concave surfaces can be used, depending on various factors such as the application, the desired optical power, etc..

As shown in <FIG> and <FIG>, each optical ray that passes through a surface Sk impinges this surface on an impact point IP. Optical rays enter optical lens system <NUM> from surface S<NUM> and pass through surfaces S<NUM> to S2N. Some optical rays can impinge on any surface Sk but cannot /will not reach image sensor <NUM>. For a given surface Sk, only optical rays that can form an image on image sensor <NUM> are considered. CH(Sk) is defined as the distance between two closest possible parallel lines, see lines <NUM> and <NUM> in <FIG> located on a plane P orthogonal to the optical axis of the lens elements. In the representation of <FIG>, plane P is parallel to plane X-Y and is orthogonal to optical axis <NUM> such that the orthogonal projection IPorth of all impact points IP on plane P is located between the two parallel lines.

The definition of CH(Sk) does not depend on the object currently imaged, since it refers to the optical rays that "can" form an image on the image sensor. Thus, even if the currently imaged object is located in a black background that does not produce light, the definition does not refer to this black background since it refers to any optical rays that "can" reach the image sensor to form an image (for example optical rays emitted by a background which would emit light, contrary to a black background).

For example, <FIG> illustrates the orthogonal projections IPorth,<NUM>, IPorth,<NUM> of two impact points IP<NUM> and IP<NUM> on plane P which is orthogonal to optical axis <NUM>. By way of example, in the representation of <FIG>, surface Sk is convex.

<FIG> illustrates the orthogonal projections IPorth,<NUM>, IPorth,<NUM> of two impact points IP<NUM> and IP<NUM> on plane P. By way of example, in the representation of <FIG>, surface Sk is concave.

In <FIG>, the orthogonal projection IPorth of all impact points IP of a surface Sk on plane P is located between parallel lines <NUM> and <NUM>. CH(Sk) is thus the distance between lines <NUM> and <NUM>.

Attention is drawn to <FIG>. According to the presently disclosed subject matter, a clear aperture CA(Sk) is defined for each given surface Sk (for <NUM> ≤ k ≤ 2N), as the diameter of a circle, wherein the circle is the smallest possible circle located in a plane P orthogonal to the optical axis <NUM> and encircling all orthogonal projections IPorth of all impact points on plane P. As mentioned above with respect to CH(Sk), the definition of CA(Sk) also does not depend on the object which is currently imaged. As shown in <FIG>, the circumscribed orthogonal projection IPorth of all impact points IP on plane P is a circle <NUM>. The diameter of circle <NUM> defines CA(Sk).

Detailed optical data and surface data are given in Tables <NUM>-<NUM> for the example of the lens elements in <FIG>. The values provided for these examples are purely illustrative, and according to other examples other values can be used.

Surface types are defined in Table <NUM>. The coefficients for the surfaces are defined in Table <NUM>. The surface types are:.

a) Plano: flat surfaces, no curvature
b) Q type <NUM> (QT1) surface sag formula: <MAT> <MAT> <MAT> <MAT> <MAT> <MAT> <MAT> 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, and An are the polynomial coefficients shown in lens data tables. The Z axis is positive towards image. Values for CA are given as a clear aperture radius, i.e. CA/<NUM>. The reference wavelength is <NUM>. Units are in mm except for refraction 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 definitions for surface types, Z axis, CA values, reference wavelength, units, focal length and HFOV are valid for Tables <NUM>-<NUM>.

Table <NUM> provides details on the variation of the properties of lens system <NUM> with the object-lens distance. The object-lens distance is defined by the distance of the object to the <NUM>st principal plane of the lens.

Table <NUM> provides details on the maximum (image-side) CRAs of lens system <NUM>. The maximum CRA and Half FOV (HFOV) are given for several object-lens distances ("Object"). Data refers to a field of <NUM>, corresponding to an edge of the image sensor (i.e. upper end of sensor diagonal).

For achieving small values of maximum CRA, the focal length fN of the last lens element LN is smaller than the lens' TTL. The TTL of lens <NUM> is <NUM>. For lens <NUM>, f<NUM> =<NUM> and a ratio of fN/TTL = <NUM>.

The focusing range of lens system <NUM> is from infinity to <NUM>. The focusing range of a lens system is defined as all object-lens distances that can be focused to by means of a camera mechanism that controls the distance between lens and image sensor. That is, for each object located within the focus range, a focusing mechanism can set a particular lens-image sensor distance that results in maximum contrast for the object's image. Maximum contrast means that for lens-image sensor distances other than the particular lens-image sensor distance, the object's contrast will decrease. The minimal object distance (MIOD) is defined as the lower limit of the focusing range, i.e. the MIOD is the smallest object-lens distance that the lens system can focus to. For lens system <NUM>, the MIOD is <NUM>. Lens system <NUM> can focus continuously from infinity to <NUM>, i.e. any focus position between Infinity to <NUM> (as well as any magnification between <NUM> and -<NUM>) can be realized.

For focusing lens <NUM>, all lens elements are moved together. For changing focus from infinity to <NUM>, a lens movement ("lens stroke") of <NUM> is required. For moving the lens, an actuator as known in the art may be used, e.g. a voice coil motor (VCM). A Hall sensor-magnet geometry for large stroke linear position sensing which is required for VCMs supporting large strokes such as <NUM> or more is described in the <CIT>. At the MIOD, lens system <NUM> achieves a magnification of -<NUM>, corresponding to an object-image ratio of ca. <NUM>:<NUM>. The HFOV decreases from <NUM> degrees when focused to infinity to <NUM> degrees when focused to the MIOD.

For any object within the focus range, lens system <NUM> has a maximum field curvature (MFC) smaller than <NUM>. MFC may be defined as follows: when placing a lens such as lens <NUM> at a distance v from a flat image sensor such as image sensor <NUM>, image points at the optical axis will be in perfect focus, but image points off the optical axis will come into focus not at the image sensor, but at a distance v' smaller than v, wherein v' is less than MFC for all image points.

A lens such as lens <NUM> can be divided into two lens groups, a first lens group ("focusing group" or "G1") and a second lens group ("CRA correction group" or "G2"). In lens <NUM>, the focusing group includes lens elements L<NUM>, L<NUM>, L<NUM> and L<NUM>. The CRA correction group includes L<NUM> and L<NUM>. The focusing group and the CRA correction group are separated spatially from each other by a big gap (BG) of <NUM>. All lens elements of G1 together have an EFL1 = <NUM>. All lens elements of G2 together have an EFL2 = <NUM>.

In another lens system embodiment <NUM> shown in <FIG> and for achieving a folded lens system with low f/# and low lens height at the same time, lens elements are cut to a non-circular shape ("D-cut"). The cut lens elements may be obtained by cutting the large lens elements of lens <NUM> to a height of e.g. <NUM> (in Y direction), so that the lens is now a cut lens <NUM>-C. That is, the lens elements Li of lens <NUM> that have height HLi > <NUM> (i.e. L<NUM>, L<NUM> and L<NUM>) are cut to <NUM>. Lens elements are cut in the Y-direction. The cut is performed symmetrically, i.e. the cut top part (defined by larger Y values in <FIG>) is identical in size to the cut bottom (defined by smaller Y values in <FIG>). The cut lens elements in <NUM>-C have no circular symmetry like that of lens elements <NUM>; their width is larger than their height, i.e. WLi > HLi (see example in <FIG>). Lens elements Li of lens <NUM> that have height HLi ≤ <NUM> are not changed. As to the cut, cut lens elements L<NUM>, L<NUM> and L<NUM> have a large CA but still low CH. This is beneficial as in a folded lens design in which a lens height HL may determine the camera's height, wherein the camera height is limited in general by a height of the host device. A folded lens having large CA and low CH is beneficial for having a low f/# folded lens that is compatible with e.g. a smartphone's height constraints. The CA of lens elements L<NUM>, L<NUM> and L<NUM> may be oriented in any direction, e.g. in Y direction. As of the cut design, the CA of lens element L<NUM>, L<NUM> and L<NUM> is oriented in the X direction (not visible here).

Light is lost at extreme rays by cutting the lens elements, but no light loss is expected for center rays. Light loss is given as percentage of rays-through at the image plane at an image sensor boundary having coordinates (X, Y) = (<NUM>, <NUM>), i.e. moving up from the optical axis by <NUM>:.

In other embodiments, only one or only two lens elements Li may be cut, i.e. may have WLi > HLi. In yet other embodiments, more than three lens elements Li may be cut, i.e. may have WLi > HLi. In yet other embodiments, all lens elements Li may be cut, i.e. may have WLi > HLi. In yet other embodiments, a cut lens may be achieved by cutting the large lens elements of lens <NUM> to a height of e.g. <NUM>, <NUM> or <NUM> (in the Y direction), i.e. lens elements Li that have height HLi > <NUM>, <NUM> or <NUM> may be cut to <NUM>, <NUM> or <NUM> respectively.

Attention is now drawn to <FIG>, which depicts schematically another optical lens system disclosed herein and numbered <NUM>. Lens system <NUM> comprises a lens <NUM>' with a plurality of lens elements, optical element <NUM> (optional) and image sensor <NUM>. Ray tracing is provided as in <FIG>. Detailed optical data and surface data are given in Tables <NUM>, <NUM>, <NUM> and <NUM>. Table <NUM> provides details on the maximum CRAs of lens system <NUM>. Notation and field are identical to Table <NUM>.

<FIG> shows <NUM> fields with <NUM> rays for each: the upper marginal-ray, the lower marginal-ray and the chief-ray.

The focusing range of lens system <NUM> is from infinity to <NUM>, i.e. the MIOD is <NUM>.

For focusing with lens <NUM>', all lens elements are moved together. For changing focus from infinity to <NUM>, a lens stroke of <NUM> is required. For moving the lens, an actuator as known in the art may be used, e.g. a VCM. At the MIOD, lens system <NUM> achieves a magnification of -<NUM>, corresponding to an object-image ratio of ca. <NUM>:<NUM>. The HFOV decreases from <NUM> degrees when focused to infinity to <NUM> degrees when focused to the MIOD. Any focus position between infinity to <NUM> (as well as any magnification between <NUM> and -<NUM>) can be realized. For any object within the focus range, lens system <NUM> has a maximum field curvature (MFC) < <NUM>.

Lens <NUM>' can be divided into two groups, a first focusing group which includes lens elements L<NUM>, L<NUM>, L<NUM>, L<NUM> and L<NUM> and a second CRA correction group which includes L<NUM> and L<NUM>. The focusing group and the CRA correction group are separated spatially from each other by a big gap of <NUM>. All lens elements of G1 together have an EFL1 = <NUM>, all lens elements of G2 together have an EFL2 = <NUM>. The TTL of lens <NUM>' is <NUM>.

<FIG> an embodiment numbered <NUM> of a lens system with a D-cut lens <NUM>'-C based on lens <NUM>'. As in the description of <FIG>, light loss is given as percentage of rays-through at coordinates (X, Y) = (<NUM>, <NUM>):.

D-cut lens <NUM>'-C is obtained by cutting the large lens elements of lens <NUM>' to a height of e.g. <NUM> (in the Y direction), i.e. the lens elements Li of lens <NUM>' that have height HLi > <NUM> (i.e. L<NUM>, L<NUM> and L<NUM>) are cut to <NUM>. In other embodiments, a cut lens may be achieved by cutting the large lens elements of lens <NUM>' to a height of e.g. <NUM>, <NUM> or <NUM> (in the Y direction), i.e. the lens elements Li that have height HLi > <NUM>, <NUM> or <NUM> may be cut to <NUM>, <NUM> or <NUM> respectively. For details on cut lenses it is referred to the description of <FIG>.

<FIG> depicts schematically another optical lens system disclosed herein and numbered <NUM>. Lens system <NUM> comprises a lens <NUM>", optical element <NUM> (optional) and image sensor <NUM>. Ray tracing is provided as in <FIG>. Detailed optical data and surface data are given in Tables <NUM>, <NUM>, <NUM> and <NUM>. Table <NUM> provides details on the maximum CRAs of lens system <NUM>. Notation and field are identical to Table <NUM>.

<FIG> shows <NUM> fields with <NUM> rays for each: the upper marginal-ray, the lower marginal-ray and the chief-ray. The focusing range of lens system <NUM> is from infinity to <NUM>, i.e. the MIOD is <NUM>. For focusing with lens <NUM>", all lens elements are moved together. For changing focus from Infinity to <NUM>, a lens stroke of <NUM> is required. For moving the lens, an actuator (e.g. a VCM) as known in the art may be used. At the MIOD, lens system <NUM> achieves a magnification of -<NUM>, corresponding to an object-image ratio of ca. <NUM>:<NUM>. The HFOV decreases from <NUM> degrees when focused to infinity to <NUM> degrees when focused to the MIOD. Any focus position between Infinity to <NUM> (as well as any magnification between <NUM> and -<NUM>) can be realized. For any object within the focus range, lens system <NUM> has a MFC < <NUM>.

Lens <NUM>" can be divided into two groups, a first focusing group that includes L<NUM>, L<NUM>, L<NUM>, L<NUM> and L<NUM> and a second CRA correction group that includes L<NUM>, L<NUM> and L<NUM>. The focusing group and the CRA correction group are separated spatially from each other by a big gap of <NUM>. All lens elements of G1 together have an EFL1 = <NUM>, all lens elements of G2 together have an EFL2 = <NUM>. The TTL of lens <NUM>" is <NUM>.

<FIG> shows an embodiment numbered <NUM> of a lens system with a cut lens <NUM>"-C based on lens <NUM>". As in the description of <FIG>, light loss is given as percentage of rays-through at coordinates (X, Y) = (<NUM>, <NUM>):.

<NUM>"-C is obtained by cutting the large lens elements of lens <NUM>" to a height of e.g. <NUM> (in Y direction). The lens elements Li of lens <NUM>" that have height HLi > <NUM> (i.e. L<NUM>, L<NUM>, L<NUM>, L<NUM> and L<NUM>) are cut to <NUM>. In other embodiments, a cut lens may be achieved by cutting the large lens elements of lens <NUM>" to a height of e.g. <NUM>, <NUM> or <NUM> (in the Y direction). For details on cut lenses it is referred to the description of <FIG>.

Attention is now drawn to <FIG>, which depict schematically yet another optical lens system disclosed herein and numbered <NUM>. Lens system <NUM> comprises a lens <NUM>‴, optical element <NUM> (optional) and image sensor <NUM>. Ray tracing is provided as in <FIG>. Detailed optical data and surface data are given in Tables <NUM>, <NUM>, <NUM>, <NUM> and <NUM>. Table <NUM> provides details on the Max CRAs of lens system <NUM>. Notation and field are identical to Table <NUM>. <FIG> show three fields with <NUM> rays for each: the upper marginal-ray, the lower marginal-ray and the chief-ray.

<FIG> shows lens system <NUM> focused to infinity ("Config. A"), <FIG> shows lens system <NUM> focused to <NUM> ("Config. B") and <FIG> shows lens system <NUM> focused to <NUM> ("Config. The object-lens distance focused on is given by Surface <NUM> in Table <NUM>. The focusing range of lens system <NUM> is from infinity to <NUM>, i.e. the MIOD is <NUM>.

Lens <NUM>‴ is divided into two groups that move relative to each other for focusing. A first lens group ("G1") includes lens elements L<NUM> and L<NUM>, and a second lens group ("G2") includes L<NUM>, L<NUM>, L<NUM> and L<NUM>. The big gap of between G1 and G2 decreases from <NUM> when focused to Infinity to <NUM> when focused to <NUM>, and to <NUM> when focused to <NUM> (see Surface # <NUM> in table <NUM>). For focusing, lens <NUM>‴ also moves as one unit so that the BFL changes (see Surface # <NUM> in Table <NUM>).

For moving the lens, an actuator (e.g. VCM) may be used, At the MIOD, lens system <NUM> achieves a magnification of -<NUM>, corresponding to an object-image ratio of ca. <NUM>:<NUM>. The HFOV decreases from <NUM> degrees when focused to infinity to <NUM> degrees when focused to the MIOD (see Table <NUM>). Any focus position between Infinity to <NUM> (as well as any magnification between <NUM> and -<NUM>) can be realized.

For any object within the focus range, lens system <NUM> has a MFC < <NUM>. All lens elements of G1 together have an EFL1 = <NUM>, all lens elements of G2 together have an EFL2 = <NUM>. The TTL of lens <NUM>‴ is <NUM>.

<FIG> shows an embodiment numbered <NUM> of a lens system with a cut lens <NUM>‴-C based on lens <NUM>‴. As in the description of <FIG>, light loss is given as percentage of rays-through at coordinates (X, Y) = (<NUM>, <NUM>):.

Cut lens <NUM>‴-C is obtained by cutting the large lens elements of lens <NUM>‴ to a height of <NUM> (in Y direction), i.e. the lens elements Li of lens <NUM>‴ that have height HLi > <NUM> (L<NUM>, L<NUM>, L<NUM> and L<NUM>) are cut to <NUM>. In other embodiments, a cut lens may be achieved by cutting the large lens elements of lens <NUM>‴ to a height of e.g. <NUM>, <NUM> or <NUM> (in the Y direction).

For details on cut lenses it is referred to the description of <FIG>.

Table <NUM> shows an overview on the EFLs of all lens elements of the G1 and G2 respectively as well as ratios EFL1/EFL2 for lens system embodiments <NUM>, <NUM>, <NUM>, <NUM> and <NUM>.

<FIG> depicts schematically another optical lens system disclosed herein and numbered <NUM>. Lens system <NUM> comprises a lens 204ʺʺ with a plurality of lens elements, optical element <NUM> (optional) and image sensor <NUM>. Ray tracing is provided as in <FIG>.

Detailed optical data, surface data and further lens properties are given in Tables <NUM>, <NUM>, <NUM> and <NUM>.

The focusing range of lens system <NUM> is from infinity to <NUM> (MIOD=<NUM>).

For focusing with lens 204ʺʺ, all lens elements are moved together. For changing focus from infinity to <NUM>, a lens stroke of <NUM> is required. At the MIOD, lens system <NUM> achieves a magnification of -<NUM>, corresponding to an object-image ratio of ca. <NUM>:<NUM>. The HFOV decreases from <NUM> degrees when focused to infinity to <NUM> degrees when focused to the MIOD. Any focus position between infinity to <NUM> (as well as any magnification between <NUM> and -<NUM>) can be realized. For any object within the focus range, lens system <NUM> has a MFC < <NUM>.

Lens 204ʺʺ can be divided into two groups, a first focusing group that includes L<NUM>, L<NUM>, L<NUM>, L<NUM> and L<NUM> and a second CRA correction group that includes L<NUM>, L<NUM> and L<NUM>. The focusing group and the CRA correction group are separated spatially from each other by a big gap of <NUM>. All lens elements of G1 together have an EFL1 = <NUM>, all lens elements of G2 together have an EFL2 = <NUM>. The TTL of lens 204ʺʺ is <NUM>.

Some embodiments may include a cut lens based on lens 204ʺʺ. The cut lens may be achieved by cutting the large lens elements of lens 204ʺʺ to a height of e.g. <NUM>, <NUM> or <NUM> (in the Y direction). For details on cut lenses, it is referred to the description of <FIG>.

According to some examples, at least part of the lens elements can have a shape (profile) in cross-section (in plane X-Y, which is orthogonal to the optical lens system and which generally coincides with the optical axis) that is not circular. In particular, as shown for example in <FIG> for a lens barrel <NUM> carrying lens elements <NUM>, at least some of the lens elements can have a width WLi (measured along axis X) which is greater than their height HLi (measured along axis Y). Barrel <NUM> further comprises a barrel wall (or surrounding) <NUM>. The height HLi can correspond to the total height of the lens element (including the mechanical part). In some embodiments, a lens element in lens barrel <NUM> may have a symmetry about axis Y and/or about axis X. A non-circular lens barrel such as <NUM> maybe shaped according to the cut lens elements of a lens such as e.g. lens <NUM>-C. As shown in <FIG>, the height of a lens barrel may be only slightly higher than the lens element having the largest height in the lens. For example, a lens barrel may be <NUM> - <NUM> higher than the highest lens element. A lens barrel having an identical height as the highest lens element is described for example in co-owned international patent application <CIT>, which is incorporated herein by reference in its entirety.

According to some examples, WLi is substantially greater than HLi (for example, by at least a percentage which is equal or greater than <NUM>%, these values being not limiting). In some examples, WLi may be greater than HLi by a percentage of <NUM>-<NUM>%. Consider lens element L<NUM> of folded lens <NUM>' as an example: WL8 is greater than HL8 by a percentage of <NUM>%.

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

Furthermore, for the sake of clarity the term "substantially" is used herein to imply the possibility of variations in values within an acceptable range. According to one example, the term "substantially" used herein should be interpreted to imply possible variation of up to <NUM>% 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 <NUM>% 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 <NUM>% over or under any specified value.

Claim 1:
A folded digital camera, comprising:
a) a lens system (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) with a lens (<NUM>, <NUM>', <NUM>", <NUM>‴, 204ʺʺ, <NUM>-C, <NUM>'-C, <NUM>"-C, <NUM>‴-C) and an image sensor (<NUM>), the lens having N ≥ <NUM> lens elements Li, an effective focal length (EFL) and a total track length (TTL), wherein each lens element has a respective focal length fi and wherein a first lens element L<NUM> faces an object side; and
b) an optical path folding element (OPFE) (<NUM>) for providing a folded optical path between an object and the lens,
wherein the lens system has a focusing range that covers object-lens distances from infinity to a minimal object distance (MIOD), and wherein <NUM> ≤ MIOD/EFL < <NUM>,
wherein the lens elements are divided into two lens element groups separated by a big gap greater than TTL/<NUM>.