TWI794934B - Folded camera lens designs - Google Patents

Abstract

Folded lens modules and assemblies characterized by low height and large entrance pupil (clear aperture), designed for folded cameras in consumer electronics and specifically in mobile phones. In some embodiments, a folded lens assembly comprises a plurality of lens elements that include, in order for an object side to an image side, a first lens element L1 with a clear aperture CA(S1) and a second lens element L2 with a clear aperture CA(S3), wherein CA(S1)/CA(S3) ＞ 1.2 and wherein the lens assembly has a ratio between an image sensor diagonal length SDL and a clear aperture of a last lens element surface CA(S2N), SDL/CA(S2N) ＞ 1.5.

Description

Folding Camera Lens Design

The subject matter of the present disclosure relates generally to the field of digital cameras.

One camera (also called "sub-camera") with a wide field of view ("wide-angle sub-camera") and another dual-aperture zoom camera (also called "dual-camera") with a narrow field of view ("telephoto sub-camera") ”) is already known.

International Patent Publication WO 2016/024192, which is hereby incorporated by reference in its entirety, discloses a "folding camera module" (also referred to simply as a "folding camera") that reduces the height of a compact camera. In order to tilt the light propagation direction from perpendicular to the back surface of the smartphone to parallel to the back surface of the smartphone, in the foldable camera, an optical path folding element (also called "OPFE"), such as a prism or a mirror, is added (also collectively referred to herein as "reflective elements"). If the folded camera is part of a dual aperture camera, a folded light path is thus provided by a lens assembly (eg a telephoto lens). This camera is referred to herein as a "folded lens dual aperture camera". Typically the camera may be contained within a multi-aperture camera, for example together with two "non-folding (upright)" camera modules within a triple-aperture camera.

The small height of a folding camera is very important to keep a host device containing it (such as a smartphone, tablet, laptop or smart TV) as thin and light as possible. Industrial design often limits the height of the camera. In contrast, increasing the optical path of the lens results in an increase in the amount of light reaching the image sensor and improves the optical properties of the camera.

Therefore, it is desirable and beneficial to provide a folded camera that maximizes the height of the lens optical path for a given camera height and/or for a lens module height.

In an exemplary embodiment, a high optical performance lens (or "lens assembly") having a large front clear aperture (CA), a large first surface clear aperture, and a relatively small clear aperture is provided. aperture of all other lens elements. The lens elements are listed in order from an object side (first lens element L1 ) to an image side (last lens element L2 ). In each embodiment, the final lens element clear aperture is less than the diagonal length (also referred to herein as "sensor diagonal length") of an image sensor of the lens included in a digital camera. or "SDL"). In the tables that follow, all dimensions are indicated in millimeters. All terms and abbreviations as known in the art have their usual meanings.

In some embodiments, there is provided a folded lens assembly for a folded camera, comprising: a plurality of lens elements, in order from an object side to an image side, including a first lens element L1 having a clear aperture CA(S1) and A second lens element L2 having a clear aperture CA(S3), where CA(S1)/CA(S3)>1.2 and where the lens assembly has an image sensor diagonal length SDL and a final lens A ratio between a clear aperture CA(S2N) on the surface of the component, SDL/CA(S2N)>1.5.

In some embodiments, the first lens component has positive power and the second lens component has negative power, and wherein the plurality of lens components further includes a third lens component with positive power and a fourth lens component with negative power lens assembly.

In some embodiments, the first lens component has positive power and the second lens component has negative power, and wherein the plurality of lens components further includes a third lens component with positive power and a fourth lens component with positive power lens assembly.

In some embodiments, the first lens component has positive power and the second lens component has negative power, and wherein the plurality of lens components further includes a third lens component with negative power and a fourth lens component with positive power. lens assembly.

In some embodiments, the plurality of lens components further includes a fifth lens component having negative refractive power.

In some embodiments, the lens assembly has a total track length (TTL) and a back focal length (BFL) and wherein a ratio BFL/TTL>0.35.

In some embodiments, an optical window is positioned within a path defining the BFL and the TTL.

In some embodiments, there is provided a folded lens assembly for a folded camera, comprising: N lens elements, in the order from an object side to an image side, including a first lens element L1 having a clear aperture CA(S1), wherein all the clear apertures of all other lens elements L2 through LN of the N lens elements are not larger than CA(S1), wherein the folded camera includes an image sensor having a sensor diagonal length SDL, and wherein CA( S1)<SDL<1.5xCA(S1).

Non-limiting examples of embodiments disclosed herein are described below with reference to the drawings listed following this paragraph. The drawings and descriptions are intended to illustrate and clarify the embodiments disclosed herein and should not be considered limiting in any way. The same elements in different drawings may be indicated by the same drawing number. Elements in the drawings are not necessarily drawn to scale. In the drawings: Figure 1A is a generally isometric view of an example of a known folding camera.

Figure 1B is a side view of the camera of Figure 1A.

Figure 1C is a generally isometric view of an example of a known camera including a folded tele sub-camera and wide angle sub-camera.

Figure 1D is a side view of the camera of Figure 1C.

FIG. 2A is a schematic diagram of an example of a lens element with light rays, according to some examples of the disclosed subject matter.

Figure 2B is another schematic view of the lens element of Figure 2A.

FIG. 3A is a schematic diagram of the point of impact of an optical ray striking a convex surface of a lens element, and a schematic diagram of the orthogonal projection of the point of impact on a plane P, according to some examples of the disclosed subject matter.

FIG. 3B is a schematic diagram of the point of impact of an optical ray striking a concave surface of a lens element, and a schematic diagram of the orthogonal projection of the point of impact on a plane P, according to some examples of the disclosed subject matter.

FIG. 4 is a schematic diagram of the orthogonal projection of the impact point on a plane P, and a schematic diagram of a headroom value ("CH"), according to some examples of the presently disclosed subject matter.

FIG. 5 is a schematic diagram of the orthogonal projection of the impact point on a plane P, and a schematic diagram of a clear aperture value ("CA") according to some examples of the presently disclosed subject matter.

FIG. 6 is a schematic diagram of another embodiment of a lens element with light rays, according to some examples of the disclosed subject matter.

FIG. 7 is also a schematic diagram of another embodiment of a lens element with light rays, according to some examples of the disclosed subject matter.

FIG. 8 is a schematic diagram of another embodiment of a lens element with light rays, according to some examples of the disclosed subject matter.

FIG. 9 is a schematic diagram of another embodiment of a lens element with light rays, according to some examples of the disclosed subject matter.

FIG. 10 is a schematic diagram of another embodiment of a lens element with light rays, according to some examples of the disclosed subject matter.

FIG. 11 is a schematic diagram of another embodiment of a lens element with light rays, according to some examples of the disclosed subject matter.

FIG. 12 is a schematic diagram of another embodiment having a lens element with light rays, according to some examples of the disclosed subject matter.

FIG. 13 is a schematic side view of an optical lens module holding the lens element, according to some examples of the disclosed subject matter.

FIG. 14A is a schematic diagram of another embodiment of a lens element displaying light according to another example of the disclosed subject matter.

Figure 14B is another schematic view of the lens element of Figure 14A.

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 subject matter of the present disclosure.

It is to be understood 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 disclosed subject matter that are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination.

The term "processing unit" disclosed herein should be broadly interpreted to include any kind of electronic device having data processing circuitry, including, for example, a computer processing device ( Such as digital signal processor (DSP), microcontroller, field programmable gate array (FPGA), application-specific integrated circuit (ASIC), etc.).

Also, for the sake of clarity, the term "substantially" is used herein to imply the likelihood that the value of the index will vary within an acceptable range. According to one example, the term "substantially" as used herein should be interpreted to imply that a variation of up to 10% is possible above or below any specified value. According to another example, the term "substantially" as used herein should be interpreted to imply that a variation of up to 5% is possible above or below any specified value. According to another example, the term "substantially" as used herein should be interpreted to imply a possible variation of up to 2.5% above or below any specified value.

1A and 1B illustrate a digital folding camera 100 that may operate, for example, as a telephoto camera. Digital camera 100 includes a first reflective element (such as a mirror or prism, sometimes referred to as an "optical path folding element" (OPFE)) 101, a plurality of lens elements (not shown in this figure, but such as in FIG. 2A It can be seen in FIG. 2B ) and an image sensor 104 . The lens element (also the lens barrel, the optical lens module) may have axisymmetric along a first optical axis 103 . At least some of the optical elements are maintained by a structure called a "mirror barrel" 102 . An optical lens module includes the lens element and the mirror barrel. The mirror barrel may have a longitudinal symmetry along the optical axis 103 . In Figures 1A to 1D, the section of the mirror barrel is circular. However this is not mandatory and other shapes may be used.

The path of the optical line from an object (not shown) to an image sensor 104 defines an optical path (see optical paths 105 and 106, which represent portions of the optical path.)

The optical path folding element 101 may be a prism or a mirror. As shown in FIG. 1A , the optical path folding element 101 may be a mirror inclined relative to the optical axis 103 . In other cases (not shown, see eg PCT/IB2017/052383), the optical path folding element 101 may be a prism with a back surface that is inclined relative to the optical axis 103 . The optical path folding element folds the optical path from a first optical path 105 to a second optical path 106 . The optical path 106 is substantially parallel to the optical axis 103 . This optical path is thus called a "folded optical path" (indicated by optical paths 105 and 106) and camera 100 is called a "folded camera".

In particular, in some examples, optical path folding element 101 may be substantially inclined 450 relative to optical axis 103 . In FIG. 1A , the optical path folding element 101 is also substantially inclined 450 relative to the optical path 105 .

In some known examples, the image sensor 104 is located in an X-Y plane substantially perpendicular to the optical axis 103 . However, this is not a limitation and the image sensor 104 can have a different orientation. For example, the image sensor 104 may be in the X-Z plane as described in WO 2016/024192. In this case, an additional optical path folding element can be used to reflect the optical line towards the image sensor 104 .

According to some embodiments, the image sensor 104 has a rectangular shape. According to some embodiments, the image sensor 104 has a circular shape. However, these examples are not limitations.

In various examples, the camera 100 may be mounted on a substrate 109, such as a printed circuit board, as is known in the art.

Two sub-cameras, such as a wide-angle sub-camera 130 and a telephoto sub-camera 100 may be included in a digital camera 170 (also called a dual camera or a dual aperture camera). A possible configuration is described with reference to Figures 1C and 1D. In this example, the tele sub-camera 100 is described in terms of this camera with reference to FIGS. 1A and 1B. Therefore, the components of the tele sub-camera 100 have the same reference numerals as in FIGS. 1A and 1B and will not be described again.

The wide-angle sub-camera 130 may include an aperture 132 (indicating the object side of the camera) and an optical lens module 133 (or "wide-angle lens module") having a symmetry (and optical) axis 134 in the Y direction, and A wide-angle image sensor 135 . The wide-angle lens module is configured to provide a wide-angle image. The wide angle sub-camera has a wide field of view (FOVW) and the telephoto sub-camera has a far field of view (FOVT) narrower than the wide field of view. In particular, in some examples, multiple wide-angle sub-cameras and/or multiple telephoto sub-cameras may be combined and operated in a single digital camera.

According to an example, the wide-angle image sensor 135 is located in the X-Z plane, whereas the image sensor 104 (in this example, a telephoto sensor) is located in an X-Y plane substantially perpendicular to the optical axis 130 .

In the example of FIGS. 1A-1D , camera 100 may also include (or be otherwise operably connected to) a processing device comprising one or more suitably configured processors for performing various processing operations. (not shown), such as processing the telephoto image and the wide-angle image into a fused output image.

The processing unit may include hardware (HW) and software (SW) dedicated to the operation of the digital camera. Alternatively, a processor (such as its local central processing unit) of an electronic device mounted on the camera may be adapted to perform various processing operations associated with the digital camera (including, but not limited to, processing the telephoto image and the wide-angle image become an output image).

Attention is now drawn to Figures 2A and 2B, which show schematic diagrams of lens modules having lens elements shown with optical lines, according to some examples of the presently disclosed subject matter. Lens module 200 is shown without a lens barrel. Figure 2A shows the optical line tracing of the lens module 200, while Figure 2B shows only the lens element for clarity. In addition, both figures show an image sensor 202 and an optical element 205 .

The lens module 200 includes N lens elements Li (where "i" is an integer between 1 and N). L1 is the lens element closest to the object side, and LN is the lens element closest to the image side, ie the side where the image sensor is located. All lenses and lens elements disclosed herein maintain this order. The lens element Li may be used, for example, as the lens element of the camera 100 shown in FIGS. 1A and 1B or as the lens element of the telephoto sub-camera 100 in FIGS. 1C and ID. As shown, the N lens element is axisymmetric along the optical axis 103 .

In the example of Figures 2A and 2B, N equals four. In the examples of Figures 6-12, N is equal to 5, however this is not a limitation and a different number of lens elements may be used. N can be equal to 3, 6 or 7, for example.

In the example of Figures 2A and 2B, some of the surfaces of the lens element are convex and some are concave. However, the illustrations of Figures 2A and 2B are not limiting, and depending on various factors such as the application, the desired optical power, etc., a different combination of convex and/or concave surfaces may be used.

The optical lines (their reflections after passing through a reflective element, such as the optical path folding element 101 ) pass through the lens element Li and form an image on an image sensor 202 . In the example of Figures 2A and 2B, the optical line passes through an optical element 205 (comprising a front surface 205a and a rear surface 205b, and may be, for example, a cut-off filter) before striking the image sensor 202, which Element 205 is also referred to as an "optical window" or simply "window". This is not a limitation however, and in some examples optical element 205 is absent. Optical element 205 may be, for example, an infrared (IR) filter, and/or a glass image sensor dust cover.

Each lens element Li comprises a respective front surface S2i-1 (the index "2i-1" is the number of the front surface) and a respective back surface S2i (the index "2i" is the number of the back surface ), where "i" is an integer between 1 and N. This numbering convention is used throughout this description. Alternatively, as in this specification, the lens surfaces are labeled "Sk", with k ranging from 1 to 2N. In some cases the front surface and the rear surface can be aspheric. However, this is not a limitation.

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

k

2N的一淨高值CH(Sk)，為每個表面Sk定義1

k

2N的一通光孔徑CA(Sk)。CA(Sk)與CH(Sk)定義每個透鏡元件的每個表面Sk的光學特性。 As follows, one can define 1 for each surface Sk

k

A clear height value CH(Sk) of 2N, defining 1 for each surface Sk

k

A clear aperture CA(Sk) of 2N. CA(Sk) and CH(Sk) define the optical properties of each surface Sk of each lens element.

k

2N)的每條光學線照射這個表面在衝擊點IP上。光學線從表面S1進入透鏡模組200，並且連續通過表面S2至S2N。一些光學線可以照射在任何表面Sk上，但是不能/將不會到達影像感測器202。針對一給定的表面Sk，只有可以在影像感測器202上形成一影像的光學線被認為形成取得的多個衝擊點IP。CH(Sk)定義為兩條最接近的可能平行線之間的距離(參見第4圖中位於與該透鏡元件的該光學軸正交的一平面P上的線400與401(在第3A與3B圖的圖示中，平面P平行於平面X-Y並且正交於光學軸103)，導致所有衝擊點IP在平面P上的該正交投影IPorth位於該兩條平行線之間。因此可以為每個表面Sk(前後表面，1

k

2N)定義CH(Sk)。 As shown in Figures 3A, 3B and 4, through a surface Sk (for 1

k

2N) each optical ray strikes this surface at the impingement point IP. The optical line enters the lens module 200 from the surface S1 and passes through the surfaces S2 to S2N continuously. Some optical rays may strike any surface Sk, but cannot/will not reach the image sensor 202 . For a given surface Sk, only optical lines that can form an image on the image sensor 202 are considered to form the obtained multiple impact points IP. CH(Sk) is defined as the distance between two closest possible parallel lines (see lines 400 and 401 in Figure 4 lying on a plane P orthogonal to the optical axis of the lens element (in Figure 3A and In the illustration of Figure 3B, the plane P is parallel to the plane XY and orthogonal to the optical axis 103), resulting in this orthogonal projection IPorth of all impact points IP on the plane P lying between these two parallel lines. It is therefore possible for each surface Sk (front and back surfaces, 1

k

2N) Define CH(Sk).

The definition of CH(Sk) does not depend on the object currently imaged, since it refers to the optical lines that "can" form an image on the image sensor. Thus, even if the currently imaged object is located in a black background that produces no light, the definition does not refer to this black background because it refers to any optical ray that "can" reach the image sensor to form an image (e.g. Optical rays emitted by a background that will emit light, as opposed to a black background).

For example, FIG. 3A illustrates the orthogonal projections IPorth,1 , IPorth,2 of the two impact points IP1 and IP2 on a plane P orthogonal to the optical axis 103 . For example, as in this illustration of Fig. 3A, the surface Sk is convex.

Figure 3B illustrates the orthogonal projections IPorth,3, IPorth,4 of two impact points IP3 and IP4 on a plane P. For example, in this illustration of Figure 3B, the surface Sk is concave.

In FIG. 4 , this orthogonal projection IPorth of all impact points IP of a surface Sk on a plane P lies between parallel lines 400 and 401 . Thus, CH(Sk) is the distance between lines 400 and 401 .

k

2N)定義通光孔徑CA(Sk)，作為一圓圈的該直徑，其中該圓圈是該最小可能的圓圈，該圓圈位於正交於光學軸103的一平面P內並且圍繞平面P上所有衝擊點的所有正交投影IPorth。如上該，關於CH(Sk)，注意到CA(Sk)的該定義也不取决於當前成像的物體。 Now pay attention to Figure 5. According to the subject matter of the present disclosure, for each given surface Sk (for 1

k

2N) Define the clear aperture CA(Sk) as the diameter of a circle, where the circle is the smallest possible circle, which lies in a plane P orthogonal to the optical axis 103 and surrounds all impact points on the plane P All orthographic projections of IPorth. As above, with respect to CH(Sk), note that this definition of CA(Sk) also does not depend on the currently imaged object.

As shown in FIG. 5 , the orthogonal projection IPorth of the boundary line of all impact points IP on the plane P is a circle 500 . The diameter of the circle 500 is defined as CA(Sk).

The detailed optical data as well as the surface data of ten examples (embodiments) of lenses (or lens assemblies) numbered Ex1, Ex2, . . . Ex 10 are given in the table below. Ten examples of lens assemblies Ex1 to Ex10 are also shown in Figures 2, 6, 7, 8, 9, 10, 11, 12, 13 and 14, respectively.

Characteristic table

Tables 1, 4, 7, 10, 13, 16, 19, 22, 25, and 28 provide a summary of the properties of each lens in Examples 1-10, respectively. For each lens, the following parameters are described:

- Effective focal length (EFL) in millimeters (mm).

- a total track length (TTL), in millimeters, defined as the distance from the first surface S1 of the first lens element to the image sensor. In some embodiments, an optical window A port is positioned within the total track length and is included in the total track length.

-f number f/#, (number without unit).

-Sensor Diagonal Length (SDL) in millimeters.

- Back focal length (BFL), in millimeters, the distance from the last surface S2N of the last lens element to the image sensor. In some embodiments, an optical window is positioned and included in the back focus.

- Ratio between total track length and back focus, TTL/EFL.

- The ratio between the back focal length and the effective focal length, BFL/EFL.

- The ratio CA(S1)/CA(S3) between the clear aperture (CA) of the first surface S1 of the first lens element and the clear aperture of the first surface S3 of the second lens element.

- the focal length of each lens, fi.

Surface parameter table

Tables 2, 5, 8, 11, 14, 17, 20, 23, 26 and 29 respectively provide a description of the surface of each element of each embodiment Ex1, Ex2, . . . Ex 10. For each lens element and each surface, the following parameters are described:

- Surface type (see below).

- The lens element number L and surface number.

- the radius of this surface in mm, infinity for a flat surface.

- the thickness between surface i and surface i+1.

- the surface refractive index Nd.

- the Abbe number Vd of the surface.

- The surface semi-diameter D/2.

Table of Aspheric Surface Coefficients:

Tables 3, 6, 9, 12, 15, 18, 21, 24, 27 and 30 provide a further description of the aspheric surface of each lens element in Examples Ex1, Ex2, ... Ex 10, respectively.

surface type

a) Q-type 1 surface sinking formula

where {z,r} are standard cylindrical polar coordinates, c is the paraxial curvature of the surface, k is the conic parameter, rmax is half the clear aperture of the surface, and An is the polynomial coefficient shown in the lens data sheet.

b) Uniform non-spherical surface formula:

This equation for the surface profile of each surface Sk (for k between 1 and 2N) is expressed as:

where "z" is the position of the profile of the surface Sk measured along the optical axis 103 (coordinated with the Z-axis, where z=0 corresponds to the intersection of the profile of the surface Sk with the Z-axis), " r" is the distance from the optical axis 103 (measured along an axis perpendicular to the optical axis 103), "K" is the cone factor, c=1/R, where R is the radius of curvature, An (n from 1 to 7) is the coefficient of each surface Sk in Table 2 and Table 4. This maximum value of r, "max r", is equal to D/2.

c) planar surfaces;

d) Suspension.

The values provided in these examples are merely illustrative, and according to other examples, other values may be used.

In the table below, the radius of curvature ("R"), lens element thickness ("T"), and clear aperture are expressed in millimeters.

Row "0" of Tables 1, 3, 5 and 7 describes the parameters associated with the object (not shown in the figure); the object is placed at a distance of 1 km from the system, considered an infinite distance.

Rows "1" to "8" of Tables 1 to 4 describe parameters with respect to surfaces S1 to S8, respectively. Rows "1" to "10" of Tables 5 to 8 describe parameters with respect to surfaces S1 to S10, respectively.

Lines "9", "10" and "11" of Tables 1 and 3 and lines "11", "12" and "13" of Tables 5 and 7 describe the surfaces 205a, 205b of the optical element 205, respectively And parameters of a surface 202 a of the image sensor 202 .

In row "i" of Table 1, Table 3, and Table 5 (i between 1 and 10 in Table 1 and Table 3, and between 1 and 12 in Table 5), the thickness corresponds to the This distance between surface Si and surface Si+1 measured about optical axis 103 (coordinated with the Z axis).

In row "11" of Tables 1, 3 (row "13" of Tables 5 and 7), the thickness is equal to zero, since this corresponds to the last surface 202a.

Example 1:

Example 2

Example 3

Example 4

Example 5

Example 6

Example 7

Example 8

Example 9

Example 10

Signs of refractive elements:

The following list and Table 33 summarize the design features and parameters present in the examples listed above. These properties contribute to the goal of a lightweight folded lens with a large lens component aperture: "AA": AA1≡BFL/TTL>0.35, AA2≡BFL/TTL>0.4, AA3≡BFL/TTL>0.5;" BB": BB1≡CA(S1)/CA(S3)>1.2, BB2≡CA(S1)/CA(S3)>1.3, BB3≡CA(S1)/CA(S3)>1.4; "CC": CC1 ≡T(AS to S3)/TTL>0.1, CC2≡T(AS to S3)/TTL>0.135, CC3≡T(AS to S3)/TTL>0.15; "DD": meet DD1≡STD<0.020, DD2 ≡STD<0.015, at least two gaps of DD3≡STD<0.010; "EE": meet at least 3 gaps of EE1≡STD<0.035, EE2≡STD<0.025, EE3≡STD<0.015; "FF": meet FF1 At least 4 gaps for ≡STD<0.050, FF2≡STD<0.035, FF3≡STD<0.025; "GG": GG1≡SDL/CA(S2N)>1.5, GG2≡SDL/CA(S2N)>1.55, GG3≡ SDL/CA(S2N)>1.6; "HH": power symbol sequence; "II": conform to II1≡STD<0.01 and OA_Gap/TTL<1/80, II2≡STD<0.015 and OA_Gap/TTL<1/65 At least 1 gap; "JJ": JJ1: Abbe number sequence of lens elements L1, L2 and L3 can be greater than 50, less than 30 and greater than 50; JJ2: Abbe number sequence of lens elements L1, L2, L3 Number sequence can be greater than 50, less than 30 and less than 30; "KK": KK1≡|f2/f1|>0.4, and the Abbe number sequence of lens elements L1, L2 and L3 can be greater than 50, less than 30 and less than 30 respectively;, KK2≡|f2/f1|< 0.5, and the Abbe number sequence of lens elements L1, L2 and L3 can be greater than 50, less than 30 and greater than 50 respectively; and "LL": LL1≡f1/EFL<0.55, LL2≡f1/EFL<0.45; "MM": MM1≡|f2/f1|<0.9, MM2≡|f2/f1|<0.5; and "NN": NN1≡TTL/EFL<0.99, NN2≡TTL/EFL<0.97, NN3≡TTL/EFL <0.95.

"OO": meet at least two gaps of OO1≡STD>0.020, OO2≡STD>0.03, OO3≡STD>0.040; "PP": meet PP1≡STD>0.015, PP2≡STD>0.02, PP3≡STD>0.03 "QQ": meet at least 4 gaps of QQ1≡STD>0.015, QQ2≡STD>0.02, QQ3≡STD>0.03; "RR": meet RR1≡TTL/Min_Gap>50, RR2≡TTL /Min_Gap>60, at least 3 OA_Gaps with RR3≡TTL/Min_Gap>100.

Unless otherwise stated, the use of the description "and/or" between the last two members of a selected list option indicates that a selection of one or more of the list options is appropriate and possible.

It should be understood that where the claims or specification refer to "a" or "an" element, such reference should not be construed as only one of that element.

All patents and patent applications mentioned in this specification are herein incorporated by reference in their entirety to the same extent as if each individual patent or patent application was specifically and individually indicated to be incorporated by reference herein. 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 disclosure.

Claims (9)

A folded lens assembly for a folded camera, comprising: a plurality (N) of lens elements, in the order from an object side to an image side, including a first lens element L1 having a positive refractive power and a clear aperture CA (S1), where S1 represents a first surface of L1, wherein all of the other lens elements L2 to LN of the (N) lens elements have all clear apertures no larger than CA(S1), wherein the folded camera includes an image sensor An image sensor of diagonal length SDL, where CA(S1)<SDL, where the folded lens assembly has a total track length (TTL) and a back focal length (BFL), where BFL/TTL>0.35, where the Total Track Length (TTL) is the distance from the first surface of the first lens element L1 to the image sensor, where the Back Focus Length (BFL) is the distance from the last surface of the last lens element LN to the image sensor distance. In the folded lens assembly of claim 1, the lens elements include a second lens element L2 with negative refractive power. As in the folded lens assembly of claim 2, wherein the lens elements include a third lens element L3 with positive refractive power. In the folded lens assembly of claim 3, the lens elements include a fourth lens element L4 with negative refractive power. As in the folded lens assembly of claim 3, wherein the lens elements include a fourth lens element L4 with positive refractive power. In the folded lens assembly of claim 1, the lens elements include a third lens element L3 with negative refractive power. As in the folded lens assembly of claim 6, wherein the lens elements include a fourth lens element L4 with positive refractive power. The folded lens assembly according to any one of the claims 1 to 7, wherein the lens elements include a fifth lens element L5 with negative refractive power. The folded lens assembly according to any one of claims 1 to 7, wherein an optical window is positioned between the folded lens assembly and the image sensor.

Images