Flex camera lens design

Abstract

A folded camera having a total track length (TTL), an f-number smaller than 1.2, and a large field of view, e.g., at least 60°. Such a folded camera may comprise: (i) a lens having N≧7 lens elements; (ii) an image sensor; and (iii) an optical path bending element for providing a folded optical path between an object and the lens, where an aperture stop of the lens is located closer to a first surface of a first lens element facing the object than a distance d that satisfies d / TTL=0.2.

Description

Detailed Description of the Invention

[0001] [Cross-reference to existing applications] This application claims priority to U.S. Provisional Patent Application No. 63 / 054,862, filed July 22, 2020, the entirety of which is incorporated herein by reference.

[0002] [Field] The subject matter of this disclosure relates generally to the field of digital cameras, and more particularly to folded optical designs in such cameras.

[0003] [Definition] In this application, the following symbols and abbreviations are used for optical and other properties referred to throughout the specification and drawings, all of which are known in the art: - Total track length (TTL): the length of the first lens element L of a lens (or "lens assembly"), measured along a direction parallel to the optical axis, when the camera system including the lens is focused at an infinite object distance. 1 Front of S 1 The maximum distance between the point and the image sensor.

[0004] Back focal length (BFL): the length of the last lens element L of a lens (or "lens assembly"), measured along a direction parallel to the first optical axis, when the camera system including the lens is focused at an infinite object distance. N Rear S 2N The minimum distance between a point and the image sensor.

[0005] -Effective focal length (EFL): Lens element L 1 ~L N The distance between the rear principal point P' and the rear focal point F' of the lens assembly.

[0006] - f-number (f / #): The ratio of the EFL to the entrance pupil diameter.

[0007] 〔background〕 Dual or triple cameras (or generally multi-cameras) are known for mobile devices such as smartphones. In a typical triple camera, one camera has an ultra-wide (UV) field of view (FOV). UW and another camera has FOV UW Narrower than Wide FOV W and another camera has FOV W Narrower FOV than Tele T In this specification, these cameras are also referred to as ultra-wide (or UW) camera, wide (or W) camera, and telephoto (or T) camera, respectively. In general, the wide camera is considered to be the main camera of a smartphone.

[0008] The f / # of a camera lens is the ratio of its effective focal length (EFL) to the diameter D of the camera's entrance pupil: f / #=EFL / D. The entrance pupil is the optical image of the aperture stop as it is "seen" through the front aperture of the lens system. The front aperture is the opening on the object side of the lens. A small f / # is desirable for a smartphone main camera because, as discussed below, it has three main advantages: good low light sensitivity, a strong "natural" Bokeh effect, and high image resolution: 1. Low light sensitivity is the main performance drawback of today's mobile device compatible cameras compared to, for example, digital single-lens reflex (DSLR) cameras. For example, halving the f / # of a camera (for the same EFL) results in four times the aperture area. This means that four times more light enters the camera. This difference is especially important when capturing low-light scenes.

[0009] 2. Bokeh is the aesthetic quality of blur in out-of-focus image parts and is a highly desired feature in today's smartphones. The bokeh effect is inversely related to the image depth of field (DOF), where DOF~f / #. A small f / # is beneficial to support a strong "natural" bokeh effect. The f / # in today's smartphone cameras does not provide enough "natural" bokeh, so the demand for strong bokeh is met by "artificial" bokeh, i.e., artificially adding blur to out-of-focus image parts.

[0010] 3. Image sensors making their way into mobile devices are constantly increasing in pixel resolution. In 2019, pixel resolution exceeded 100 megapixels for the first time. This is achieved (among other factors) by shrinking the size of a single pixel, i.e., by increasing the spatial pixel frequency. To convert pixel resolution to image resolution, the camera lens increases the spatial pixel frequency k of the sensor. Pixel For a well-designed (diffraction-limited) camera lens, the resolvable spatial frequency k of the lens must be supported. Lens depends on the inverse of f / #: k Lens ∼1 / f / #, i.e. smaller f / # corresponds to greater image resolution (assuming an image sensor with sufficient spatial pixel frequency).

[0011] Latest premium smartphones have a main wide camera with f / # of about f / 1.9 (Huawei P40 Pro) and f / 1.8 (Apple iphone 11 Pro Max). The main challenge for cameras with small f / # is to design lenses that correct the strong aberrations due to the large front aperture required, e.g., chromatic aberration. This challenge is usually addressed by designing more complex lenses with more lens elements. However, the total track length (TTL) and camera module height are generally larger as a result. This is detrimental to the goal of designing slim smartphones.

[0012] Recent developments in mobile telecameras include using prisms to "fold" the telecamera: a reflective element or optical path folding element ("OPFE") is added to the optical path to "bend" (deflect) the direction that the light propagates from perpendicular to the rear face of the host device to parallel to the rear face of the host device. Folded cameras allow for large TTL in slim camera designs.

[0013] An improvement to a smartphone's main camera would benefit from having a curved wide camera design with a smaller f / #.

[0014] 〔overview〕 In various embodiments, (i) N≧7 lens elements L i and having an effective focal length (EFL), i are the focal lengths f i and the first lens element L 1is provided a folded camera comprising: (i) a lens facing an object side; (ii) an image sensor; and (iii) an OPFE for providing a folded optical path between an object and the lens with respect to a lens optical axis, the folded camera having a total track length (TTL), an aperture stop of the lens is located closer to a first surface of the first lens element facing the object than a distance d such that d / TTL=0.2, and an f-number f / # of the folded camera is smaller than 1.2.

[0015] In various embodiments, (i) a lens element L having an effective focal length (EFL) and a first optical axis and N≧7 i each lens element having a respective focal length f i and each of the front surfaces S 2i-1 and each rear surface S 2i a plurality of said lens element surfaces are S k (where 1≦k≦2N) and each lens element surface S k is the clear height value CH(S k ) and has a surface S 17 Clear height value CH(S 17 ) is the surface S 2 From surface S 2N-1 In one embodiment, a folded camera is provided, comprising: (i) a lens having a height equal to or greater than a clear height value of each surface up to and including a clear height of the first surface; (ii) an image sensor; and (iii) an OPFE for providing a folded optical path between an object and a plurality of said lens elements, wherein an f-number f / # of the folded camera is less than 1.2.

[0016] In some embodiments, f / #<1.1.

[0017] In some embodiments, f / #≦1.0.

[0018] In some embodiments, 0.8 <f / #≦1.0である。

[0019] In some embodiments, the curved cameras described above or below have a diagonal FOV greater than 60°.

[0020] In some embodiments, for 1≦i≦3, |f i |>4·EFL.

[0021] In some embodiments, for 1≦i≦3, |f i |>5·EFL.

[0022] In some embodiments, L 5 is the lens element with the strongest optical power, i.e., for i ≠ 5, |f 5 |<|f i |is.

[0023] In some embodiments, f 5 <EFLである。

[0024] In some embodiments, the lens element L 4 and lens element L 5 The sub-lens system including has a positive refractive power.

[0025] In some embodiments, L 4 Focal length f 4 and L 5 The focal length f 5 is |f 4 |<4·f 5 Meet the following.

[0026] In some embodiments, L 4 The focal length f 4 and L 5 The focal length f 5 is |f 4 |<3·f 5 Meet the following.

[0027] In some embodiments, the lens includes at least one air gap between lens elements that obeys the condition STD<0.020, where STD is the normalized gap standard deviation.

[0028] In some embodiments, the lens includes at least one air gap between lens elements that obeys the condition STD<0.010, where STD is the normalized gap standard deviation.

[0029] In some embodiments, the lens element L 4 and lens element L 5 The air gap between satisfies STD<0.020, where STD is the normalized gap standard deviation.

[0030] BRIEF DESCRIPTION OF THE DRAWINGS Non-limiting examples of the embodiments disclosed herein are described below with reference to the drawings attached hereto, listed after this paragraph. The drawings and description are intended to clarify and clarify the embodiments disclosed herein, and should not be considered limiting in any way. Like elements in various drawings may be indicated by like numerals. Elements in the drawings are not necessarily drawn to scale. In the drawings: FIG. 1A is a perspective view showing a known digital folded camera that can operate as a wide camera; FIG. 1B is a side view of the camera of FIG. 1A; FIG. 1C illustrates a known dual camera that includes a bent camera like the one in FIGS. 1A and 1B together with an "upright" (non-bent) camera; FIG. 2A is a schematic diagram illustrating a folded optical lens system according to some embodiments of the subject matter of the present disclosure; FIG. 2B is a schematic diagram illustrating another folded optical lens system according to some embodiments of the subject matter of the present disclosure; FIG. 2C is a schematic diagram illustrating yet another folded optical lens system according to some embodiments of the subject matter of the present disclosure; FIG. 2D is a schematic diagram illustrating yet another folded optical lens system according to some embodiments of the subject matter of the present disclosure; FIG. 2E is a schematic diagram illustrating yet another folded optical lens system disclosed herein; FIG. 3A shows the arrangement of two collision points IP on a plane P perpendicular to the optical axis of the lens of the system in FIGS. 2A to 2D. 1 and IP2 Orthogonal projection of IP orth,1 , IP orth,2 1 is a diagram showing the FIG. 3B shows the arrangement of two collision points IP on a plane P perpendicular to the optical axis of the lens of the system in FIGS. 2A to 2D. 3 and IP 4 Orthogonal projection of IP orth,3 , IP orth,4 1 is a diagram showing the Figure 4 shows the definition of clear height diagrammatically; FIG. 5 illustrates the definition of a clear aperture; FIG. 6 shows a lens element L i Diameter H Li Showing an illustration of; FIG. 7 shows the lens element width W Li and the height of the lens element H Li FIG. 2 is an exploded view of a lens element.

[0031] [Mode for carrying out the invention] 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 subject matter disclosed herein 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 disclosed herein.

[0032] It will be 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 subcombination.

[0033] Furthermore, for clarity, the term "substantially" is used herein to imply the possibility of variation of values ​​within an acceptable range. According to one example, the term "substantially" used herein should be interpreted to imply a possible variation of up to 10% above any particular value or a possible variation of up to 10% below any particular value. According to another example, the term "substantially" used herein should be interpreted to imply a possible variation of up to 5% above any particular value or a possible variation of up to 5% below any particular value. According to yet another example, the term "substantially" used herein should be interpreted to imply a possible variation of up to 2.5% above any particular value or a possible variation of up to 2.5% below any particular value.

[0034] 1A and 1B show a known digital folded camera 100 that may operate, for example, as a wide-angle camera. The camera 100 includes an optical path bending element (OPFE) 102 (e.g., a prism), a lens 104 having a number of lens elements (not visible in this depiction, but visible, for example, in FIGS. 2A-2D), and an image sensor 106. In some embodiments (such as the embodiment in FIGS. 2A-2D), the lens elements are axisymmetric along a first optical axis 108. In other embodiments, the lens elements may not be axisymmetric. For example, as illustrated in FIG. 2B, the lens elements may be cut (or diced or sliced) into a non-circular shape.

[0035] At least some of the lens elements may be held by a structure referred to as a "barrel" 110. The barrel may have longitudinal symmetry along the optical axis 108. In Figures 1A-1C, the cross section of the barrel is circular. However, this is not required and other shapes may be used, for example to hold cut lens elements.

[0036] The path of a light ray from an object (not shown) to image sensor 106 defines an optical path (see optical path 112 and optical path 114, which represent portions of an optical path).

[0037] The OPFE bends the optical path from a first optical path 112 to a second optical path 114. Optical path 114 is substantially parallel to the optical axis 108. For this reason, the optical path is referred to as a "folded optical path" (as illustrated by optical paths 112 and 114) and camera 100 is referred to as a "folded camera."

[0038] In particular, in some embodiments, OPFE 102 is tilted at substantially 45° with respect to optical axis 108. In FIG. 1A, OPFE 102 is also tilted at substantially 45° with respect to optical path 112.

[0039] In some known embodiments, the image sensor 106 lies in an XY plane that is substantially perpendicular to the optical axis 108. However, this is not limiting and the image sensor 106 may have a different orientation. For example, as described in WO 2016 / 024192, the image sensor 106 may be in an XZ plane. In this case, an additional OPFE may be used to reflect light rays towards the image sensor 106.

[0040] Two cameras, for example a wide camera 100 and a normal UW camera 130, may be included in the digital camera 150 (also referred to as a dual camera). A possible configuration is shown in FIG. 1C.

[0041] The UW camera 130 may include an aperture 132 (denoting the object side of the camera), an optical lens system 134 (or "wide lens module") having an axis of symmetry 136 in the Y direction, and a UW image sensor 138. The UW camera comprises a UW lens system configured to provide a UW image. As already indicated above, the UW camera has a wide camera field of view FOV W Larger FOVUW For example, FOV UW may be 80° to 130°, and FOV W In particular, in another example, multiple wide cameras and / or multiple telephoto cameras may be incorporated into a single digital camera and operated. T may be, for example, 20° to 50°.

[0042] Attention is now directed to FIG. 2A. FIG. 2A illustrates a schematic of an optical lens system (number 200) disclosed herein. Lens system 200 includes an OPFE 202, a lens (or "lens assembly") 204, an optical element 206, and an image sensor 208. System 200 is illustrated with a ray trace. Optical element 206 may be, for example, an infrared (IR) filter and / or a glass image sensor dust cover. The light rays (after being reflected by prism 202) pass through lens 204 and form an image on image sensor 208. FIG. 2A illustrates three fields, each with three rays (upper marginal ray, lower marginal ray, and chief ray). In the embodiment of FIG. 2A, the light rays pass through optical element 206 before impinging on image sensor 208. However, this is not limiting and in some embodiments, optical element 206 is not present. That is, in some lens systems, the optical element is optional.

[0043] The lens 204 includes a plurality of lens elements L i 220 (where "i" is an integer from 1 to N). 1 is the lens element closest to the object (prism), and L N 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 element L i can be used as lens elements of the above camera 100, for example. The N lens elements are axially symmetric along the optical axis 210. Each lens element L i is the front S of each 2i-1(The suffix "2i-1" is the front number), and the rear S 2i (the subscript "2i" is the number of the rear surface), where "i" is an integer from 1 to N. This numbering convention is used throughout this specification. Alternatively, as done throughout this specification, the lens surfaces may be referred to as "S k " (k runs from 1 to 2N). In some cases, the anterior and posterior surfaces may be aspheric. However, this is not limiting.

[0044] As used herein, the term "front surface" of each lens element refers to the surface of the lens element that is closer to the camera entrance (the object side of the camera), and the term "back surface" refers to the surface of the lens element that is closer to the image sensor (the image side of the camera).

[0045] In lens system 200, the first horizontal surface of the prism (oriented along the Z direction) is marked T1 and is 10.93 mm. The second horizontal surface of the prism (oriented along the X direction, not shown) is marked T2 and is 12.6 mm. The vertical surface of the prism (oriented along the Y direction) is marked V and is 8.68 mm. The prism angle is 45°. By making the prism size relatively large, a large amount of light can be allowed into the camera. This allows the camera to have an f / # as low as 1.0 in this example. In other embodiments, the f / # can be between 0.8 and 1.2. The aperture stop of lens 204 is S 2 For a non-zero field as shown in lens system 200, approximately 80% of the light reaches image sensor 208.

[0046] As explained below, each surface S k (where 1≦k≦2N), the clear height value CH(S k ) can be defined for each surface S k(where 1≦k≦2N), the clear aperture value CA(S k ) can be defined. CA(S k ) and CH(S k ) for each surface S of each lens element k In the following, the term CH is defined with reference to FIG. 4 and the term CA is defined with reference to FIG.

[0047] Furthermore, each lens element L i Regarding the height (H Li ", 1≦i≦N) are defined. Each lens element L i About H Li is the lens element L measured along a direction perpendicular to the optical axis of the lens element i For a given lens element, this height is greater than or equal to the clear height value CH and the clear aperture value CA of the front and back surfaces of the given lens element. As shown in FIG. 6, for an axisymmetric lens element, H Li is usually the lens element L i For axisymmetric lens elements, H Li =max{CA(S 2i-1 ), CA(S 2i )}+the size of the machine part.

[0048] Generally, in lens design, the size of the mechanical parts is defined as not contributing to the optical properties of the lens. For this reason, two heights of the lens are defined: the optical height H of the optically active area (the area marked with a dot) opt (corresponding to the CA value), and the geometric (or mechanical) height H of the lens spanning the optically active and optically inactive areas. L It is. Li The contribution of the size of the mechanical parts to is typically between 200 μm and 1000 μm.

[0049] In lens 204, the last lens element L 8 The last surface of S 17 The clear aperture of CA17 is the surface area of ​​all other surfaces of the lens elements S i CA is greater than i<17, i.e., CA 17 >CA i The last lens element L 8 The first surface S 16 CA 16 is the surface area S in front of the lens elements. i CA is greater than i<16, i.e., for i<16, CA 16 >CA i It is.

[0050] In lens system 200, N is equal to 8. However, this is not limiting and a different number of lens elements may be used. According to some embodiments, N is greater than or equal to 7. For example, N may be equal to 7, 8, 9, or 10.

[0051] Some of the surfaces of the lens elements in lens system 200 are depicted as convex and some as concave, however, the depiction in Figure 2A is not intended to be limiting and different combinations of convex and / or concave surfaces may be used depending on various factors such as the application, desired optical power, etc.

[0052] A lens barrel, such as lens barrel 110, may carry lens 204. In some embodiments, the lens barrel may be circular, such as lens barrel 110. In other embodiments, the lens barrel may not be circular, but may have a shape like the lens element of FIG. 7. Referring to FIG. 7, a non-circular lens barrel may have an X-axis or a Y-axis as an axis of symmetry. A non-circular lens barrel may be shaped according to a cut lens element of a lens, such as lens 204'. The height of the lens barrel may be only slightly higher than the lens element with the greatest height in the lens. For example, the lens barrel may be 0 mm to 0.5 mm higher than the tallest lens element. A lens barrel having the same height as the tallest lens element is described, for example, in commonly owned International Patent Application PCT / IB2018 / 050988, which is incorporated herein by reference in its entirety.

[0053] As shown in Figs. 3A, 3B and 4, the surface S k Each ray passing through (1≦k≦2N) impinges on the surface at an impact point IP. 1 Enter the optical lens system 200 from S 2 From S 2N Some rays pass through the surface S k , but cannot / does not reach the image sensor 208. k For CH(S, only light rays that can form an image on the image sensor 208 are considered. k ) is defined as the distance between the two closest possible parallel lines (see lines 400 and 402 in FIG. 4) located on a plane P perpendicular to the optical axis of the lens element. In the representation of FIGS. 3A and 3B, the orthogonal projection IP orth The plane P is parallel to the plane XY and perpendicular to the optical axis 103 so that CH(S k ) for each surface S k (front and back surfaces, 1≦k≦2N).

[0054] CH(S k The definition of ) does not depend on the object currently being imaged, since it refers to light 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 emit light, this definition does not refer to this black background, since it refers to any light rays that "can" reach the image sensor and form an image (e.g. light rays emitted by a background that would emit light, as opposed to a black background).

[0055] For example, FIG. 3A shows two collision points IP on a plane P perpendicular to the optical axis 103. 1 and IP 2 Orthogonal projection of IP orth,1 , IP orth,2 As an example, in the representation of FIG. 3A, the surface S k is convex.

[0056] Figure 3B shows two collision points IP 3 and IP 4 Orthogonal projection IP of onto plane P orth,3 , IP orth,4 As an example, in the representation of FIG. 3B, the surface S k is concave.

[0057] In Figure 4, the surface S k Orthogonal projection IP of all collision points IP onto plane P orth is located between the parallel lines 400 and 402. Therefore, CH(S k ) is the distance between line 400 and line 402.

[0058] Attention is now directed to FIG. 5. In accordance with the subject matter of this disclosure, a clear aperture CA(S k ) for each given surface S k (where 1≦k≦2N), this circle is defined as the diameter of a circle located in a plane P perpendicular to the optical axis 108 and defined by the orthogonal projection IP orth is the smallest possible circle that encloses CH(S k As mentioned above for CA(Sk Note that the definition of ) also does not depend on the object currently being imaged.

[0059] As shown in Figure 5, the orthogonal projection IP of all collision points IP circumscribed onto the plane P orth is the circle 500. The diameter of the circle 500 is CA(S k ) is established.

[0060] Detailed optical and surface data for examples of the lens element of Figure 2A are provided in Tables 1-3. The values ​​provided for these examples are purely exemplary, and other values ​​may be used according to other examples.

[0061] The surface types are defined in Table 1 and the surface coefficients are defined in Table 2: The surface types are: a) Plano: Flat surface, no curvature b) Q type 1 (QT1) surface sag formula:

[0062]

number

[0063] [Table 1] Values ​​for CA are given as the clear aperture radius, i.e., CA / 2. The reference wavelength is 555.0 nm. Units are in mm, except for the refractive index ("index") and Abbe number. Each lens element L i are the focal lengths f given in Table 1. i has.

[0064] [Table 2] In the embodiment of FIG. 2A, the following optical properties are achieved: -TTL=8.34mm -BFL=1.08mm -EFL=4.14mm -CA(S 17 )>CA(S k ), 1 <k≦2N -CA(S 16 )>CA(S k ), 1 <k≦2N-1 -CA(S 15 )>CA(S k ), 1 <k<2N-2 -f / #=1.0 -Sensor diagonal (SD) is 7mm, sensor width / height ratio is 4:3 -Minimum CA / SD ratio: CA(S 4 ) / SD=0.57 -Maximum CA / SD ratio: CA(S 17 ) / SD=0.94 -Diagonal FOV=80.44°, horizontal FOV=68.32°, vertical FOV=53.48°, -S from aperture stop 2 Distance d: d=-0.042mm -L 1 , L 2 and L 3 has relatively small power (magnitude), and for 1≦i≦3, |f i |>5·EFL -L 4 and L 5 Both have positive power and are separated by a thickness d. 4 and L 5 The sub-lens system, including the lens, has a focal length of 1 / (f 4 +f 5 )=[1 / f 4 +1 / f 5 -d / (f 4 f 5 )]>0 -L 5 follows the formula: 5 <EFL -L 4 and L 5 satisfies the following equation: |f 4 |<3×f 5 -L 4 and L 5 Minimum gap between: Gap Min =0.04mm -L 4 and L 5 Maximum gap between:Gap Max =0.0745mm -L 4 and L 5 Average gap between AVG 4 :AVG 4 =0.048mm -L 4 and L 5 Average gap between AVG 4 STD from (r) 4 :STD 4 =3.42 10 -3 mm.

[0065] The lens 204 may be carried by a lens barrel having a lens barrel height of, for example, 6.57 mm to 7.2 mm.

[0066] As used herein, "gap" or "air gap" refers to the space between consecutive lens elements. In the case of lens element 4 and lens element 5, the "gap" is the L 4 The last surface of L 5 This refers to the gap between the first surface of the substrate and the second surface of the substrate.

[0067] For each gap several functions and constants are defined: 1. Gap i The "(r)" function (where i is the lens element number and r is the same variable as used in Equation 1) is as follows: a) When i=1: Gap 1 (r)=L 2 S1 z(r)+(prism exit surface and L 2 S 1 the distance along the second optical axis between b) If i>1: Gap i (r)=L i+1 S 1 z(r)+(L i S 2 and L i+1 S 1 (the distance along the second optical axis between i S 2 z(r); c) For r=0, the "on-axis gap" (OA_Gap i ) is a Gap i (r=0); 2. "Gap Average" (AVG i ) constant is given by:

[0068]

number

[0069] 3. Normalized Gap Standard Deviation (STD i ) constant is given by:

[0070]

number

[0071] Attention is now directed to FIG. 2B, which shows a schematic diagram of another optical lens system (numeral 200') disclosed herein. Lens system 200' includes an OPFE 202, a lens 204' having multiple lens elements, an optical element 206, and an image sensor 208. Ray tracing is performed as shown in FIG. 2A. Detailed optical and surface data are shown in Tables 1 and 2, where L 6 and L 8 The aperture radius for the entire surface of L 7 Surface S 15 The data on the aperture radius are replaced by 2.5 mm in the y direction (no change in the x direction).

[0072] To achieve a folded lens system with a small f / # and small lens height, the lens elements are cut to a non-circular shape (often called a "cut lens" or "D-cut lens"). The lens elements are obtained by cutting the large lens elements of lens 204' to a height of 5 mm (in the Y direction). That is, the height H Li Lens element L of lens 204' having a length of >5 mm i (i.e., L 6 , L 7 and L 8 ) is cut to 5 mm. The cut lens element does not have the circular symmetry of lens element 204, but its width is greater than its height, i.e., W Li >H Li (See the example in Figure 7.) Height H Li Lens element L of lens 204 having a length of ≦5 mm i As of this cut, the lens element L 6 , L 7 and L 8 In this case, CH is small while CA is large. This is advantageous. The camera height is generally limited by the height of the host device, but in the folded lens design, the camera height is limited to the lens height H LA lens with a large CA and a small CH is beneficial for a folded lens with a small f / #, for example, to fit the height constraints of a smartphone. The lens elements of lens 204′ are cut in the Y direction. This is because the height H of the lens element can be determined by Li is its width W Li This means that the lens element L 1 ~L 5 The CA may be oriented in any direction, such as the Y direction. 6 , L 7 and L 8 The CA of the lens element L has an orientation in the X direction (not shown). In another embodiment, only one lens element L i or only two lens elements L i may be cut, i.e., W Li >H Li In yet other embodiments, the lens elements L may have more than three lens elements. i may be cut, i.e., W Li >H Li In yet another embodiment, all of the lens elements L i may be cut, i.e., W Li >H Li In other embodiments, the lens 204′ may be realized by cutting a large lens element of the lens 204 to a height of, for example, 4.5 mm or 4 mm (in the Y direction), i.e., a height H Li Lens element L having 4.5 mm i (i.e., L 4 , L 5 , L 6 , L 7 and L 8 ), or height H Li Lens element L having 4 mm i (i.e., L 1 ~L 8) may be cut to 4.5 mm or 4 mm, respectively. In yet other embodiments, lens 204' may be formed by cutting a large lens element of lens 204 to a height of, for example, 3.5 mm or 3 mm (in the Y direction).

[0073] In lens system 200', the dimensions of the prisms are identical to those in lens system 200: T1=10.93 mm, T2=12.6 mm and V=8.68 mm.

[0074] In addition to the properties described in FIG. 2A, the embodiment of FIG. 2B achieves the following optical properties: -CA(S 12 )=1.03×CH(S 12 )=2.58mm -CA(S 13 )=1.03×CH(S 13 )=2.58mm -CA(S 15 )=1.14×CH(S 15 )=2.85mm -CA(S 16 )=1.19×CH(S 16 )=2.97mm -CA(S 17 )=1.32×CH(S 12 )=3.29mm -CA(S 17 )>CA(S k ), 1 <k≦2N -CA(S 16 )>CA(S k ), 1 <k≦2N-1 -CA(S 15 )>CA(S k ), 1 <k<2N-2 -All lens surfaces CH(S k )≦5mm -f / #=1.0 -Minimum CA / SD ratio: CA(S 4 ) / SD=0.57 -Maximum CA / SD ratio: CA(S 17 ) / SD=0.71 The lens 204' may be carried by a lens barrel having a lens barrel height of, for example, 5.0 mm to 5.5 mm.

[0075] FIG. 2C illustrates a schematic diagram of another optical lens system (number 200'') disclosed herein. Lens system 200'' includes OPFE 202', lens 204, optical element 206, and image sensor 208. Ray tracing is performed as shown in FIG. 2A. Detailed optical and surface data are shown in Tables 1 and 2. Compared to the OPFE shown in FIG. 2A and FIG. 2B, OPFE 202' has a smaller prism height ("V") of 7.82 mm. A smaller prism height may be beneficial for realizing a slimmer folded camera.

[0076] where T1=9.815 mm, T2=12.6 mm and V=7.82 mm. For a non-zero field of lens system 200", the reduction in light compared to optical lens system 200 and optical lens system 200' is 8% or less. For a zero field, there is no change in the amount of light entering the camera. The high amount of light entering the camera allows for a small f / # of the camera of 1.0. In other embodiments, f / # can be between 0.8 and 1.2.

[0077] FIG. 2D illustrates a schematic diagram of yet another optical lens system (numbered 200''') disclosed herein. Lens system 200''' includes an OPFE 202'', a lens 204, an optical element 206, and an image sensor 208. Ray tracing is performed as shown in FIG. 2A. Detailed optical and surface data are shown in Tables 1 and 2. Compared with the OPFE 202' shown in FIG. 2C, the OPFE 202'' has a smaller prism height ("V") of 7.02 mm.

[0078] where T1=8.75 mm, T2=12.6 mm and V=7.02 mm. For a non-zero field of lens system 200'''', the reduction in light compared to lens system 200 and lens system 200' is 19% or less. For a zero field, there is no change in the amount of light entering the camera. The high amount of light entering the camera allows for a small f / # of the camera of 1.0. In other embodiments, the f / # can be between 0.8 and 1.2.

[0079] FIG. 2E shows a schematic diagram of yet another optical lens system (200'''') disclosed herein. Lens system 200'''' includes an OPFE 202'''', a lens 204'', an optical element 206, and an image sensor 208. Ray tracing is performed as shown in FIG. 2A. Detailed optical and surface data are shown in Tables 1 and 2, where L 6 and L 8 The aperture radius for the entire surface of L 5 Surface S 11 and L 7 Surface S 15 The data for the aperture radius is translated to 2.45 mm in the y direction (no change in the x direction). The prism height (measured along the Y axis) is greater than the height of lens 204''. The overall height of lens system 200'''' (measured along the Y axis) is determined by the prism height only, i.e. there is no additional "height penalty" introduced by lens 204''.

[0080] Compared to the OPFE 202'' shown in FIG. 2D, the OPFE 202''' has a smaller prism height of 6.00 mm.

[0081] The lens elements of lens 204″ are obtained by cutting the larger lens elements of lens 204″ to a height of 4.9 mm (in the Y direction). Li Lens element L of lens 204″ having a length of 4.9 mm i (i.e., L 6 , L 7and L 8 ) is cut to 4.9 mm. The cut lens element does not have the circular symmetry of lens element 204, but its width is greater than its height, i.e., W Li >H Li (see example in FIG. 7). In other embodiments, the lens 204″ may be realized by cutting the large lens elements of the lens 204 to a height of, for example, 4.5 mm or 4 mm (in the Y direction), i.e., a height H Li Lens element L having 4.5 mm i (i.e., L 4 , L 5 , L 6 , L 7 and L 8 ), or height H Li Lens element L having 4 mm i (i.e., L 1 ~L 8 ) may be cut to 4.5 mm or 4 mm, respectively.

[0082] Further explanation of the cut lenses is provided in the description of FIG. 2B, where T1=6.95 mm, T2=12.6 mm, and V=6.00 mm. For the non-zero field shown in lens system 200'''', about 55% to about 60% of the light reaches image sensor 208. For the non-zero field of lens system 200'''', the reduction in light is about 30% compared to the non-zero fields of lens system 200 and lens system 200'. This reduction in light is mainly due to the smaller prism dimensions and not due to the D-cutting of larger lens elements. This reduction in light occurs symmetrically for the upper and lower marginal rays. The difference in the amount of light reaching image sensor 208 for the D-cut lens and the non-D-cut lens in lens system 200'''' amounts to <5%. For the zero field, there is no change in the amount of light entering the camera. The large amount of light entering the camera allows for a small f / # of the camera of 1.0. In other embodiments, f / # may be between 0.8 and 1.2. Lens 204'' may be carried by a lens barrel having a lens barrel height of, for example, 4.9 mm to 5.5 mm.

[0083] According to some embodiments, at least some of the lens elements of the plurality of lens elements may have a cross-sectional shape (profile) (in a plane XY, perpendicular to the optical lens system and generally coinciding with the optical axis) that is not circular. In particular, as shown in FIG. 7, at least some of the lens elements of the plurality of lens elements assembled in the lens barrel 710 may have a height H Li Width (measured along the X-axis) greater than W Li The height H Li may correspond to the total height (including mechanical parts) of the lens element. In some embodiments, the lens elements in lens system 700 may have symmetry about the Y axis and / or symmetry about the X axis.

[0084] According to some embodiments, W Li is H Liis substantially larger than (e.g., W Li is H Li (However, this value is not limiting.) In some embodiments, W Li is H Li As an example, the lens element L of the folded lens 204′ may be 20% to 70% larger than the 8 Thinking about it: L8 is H L8 As another example, the lens element L of the folded lens 204″ is 8 :W L8 is H L8 44% larger than

[0085] Unless otherwise specified, the use of the expression "and / or" between the last two of listed alternatives indicates that selecting one or more of the listed alternatives is appropriate and may be made.

[0086] When a claim or the specification refers to an element preceded by the article "a" or "an," it should be understood that such a reference is not to be construed as the presence of only one of the element.

[0087] All patents and patent applications mentioned in this specification are incorporated herein 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 herein by reference. Furthermore, 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. [Brief description of the drawings]

[0088] [Figure 1A] FIG. 1 is a perspective view of a known digital folded camera that can operate as a wide camera. [Figure 1B] FIG. 1B is a side view of the camera of FIG. 1A. [Figure 1C]FIG. 1C illustrates a known dual camera that includes a curved camera such as the one in FIGS. 1A and 1B along with an “upright” (non-curved) camera. [Figure 2A] 1 is a schematic diagram illustrating a folded optical lens system according to some embodiments of the presently disclosed subject matter. [Figure 2B] 2 is a schematic diagram illustrating another folded optical lens system according to some embodiments of the subject matter disclosed herein. [Figure 2C] 2 is a schematic diagram illustrating yet another folded optical lens system according to some embodiments of the presently disclosed subject matter. [Figure 2D] 2 is a schematic diagram illustrating yet another folded optical lens system according to some embodiments of the presently disclosed subject matter. [Figure 2E] FIG. 2 is a schematic diagram illustrating yet another folded optical lens system disclosed herein. [Figure 3A] FIG. 2C shows orthogonal projections IPorth,1, IPorth,2 of two collision points IP1 and IP2 onto a plane P perpendicular to the optical axis of the lens of the system in FIGS. 2A to 2D. [Figure 3B] FIG. 2C shows orthogonal projections IPorth,3, IPorth,4 of two collision points IP3 and IP4 onto a plane P perpendicular to the optical axis of the lens of the system in FIGS. 2A to 2D. [Figure 4] The definition of clear height is shown in the figure. [Diagram 5] The definition of a clear aperture is shown in the figure. [Figure 6] 1 shows an illustration of the diameter HLi of a lens element Li. [Figure 7] FIG. 2 is an exploded view of a lens element showing the lens element width WLi and the lens element height HLi.

Claims

1. a) A lens element L having an effective focal length (EFL) and N≧7 along the lens optical axis ｉ A lens comprising a first lens element L １ a lens facing the object side; b) a lens barrel carrying the lens; c) an image sensor; and d) an optical path bending element (OPFE) that bends a first optical path parallel to a plane including the image sensor into a second optical path perpendicular to the first optical path and parallel to the lens optical axis; A bent camera comprising: The bend camera has a total track length (TTL), an aperture stop of the lens is located closer to a first surface of the first lens element that faces the object than a distance d that satisfies d / TTL=0.2; said curved camera having an f-number f / #<1.2; For 1≦i≦3, |f ｉ |>5xEFL, flexion camera.

2. a) A lens element L having an effective focal length (EFL) and N≧7 along the lens optical axis ｉ A lens comprising a first lens element L １ a lens facing the object side; b) a lens barrel carrying the lens; c) an image sensor; and d) an optical path bending element (OPFE) that bends a first optical path parallel to a plane including the image sensor into a second optical path perpendicular to the first optical path and parallel to the lens optical axis; A bent camera comprising: The bend camera has a total track length (TTL), an aperture stop of the lens is located closer to a first surface of the first lens element that faces the object than a distance d that satisfies d / TTL=0.2; said curved camera having an f-number f / #<1.2; Lens element L ４ and lens element L ５ The air gap between the STD is the normalized gap standard deviation, for the bend camera.

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