Camera

Abstract

The invention provides a camera. The camera comprises a lens system having a lens with N lens elements Li, an effective focal length (EFL) and a total track length (TTL), where N is greater than or equal to 6, where each lens element has a respective focal length fi, and where a first lens element L1 faces an object side; and an optical path folding element (OPFE) for providing a folded optical path between the object and the lens. In some embodiments, the lens system has a focus range covering from infinity to a minimum object distance (MIOD), where minimum object distance / effective focal length (MIDO / EFL) is less than 20 or less than 7. In some embodiments, when the folding digital camera is focused at infinity, a ratio (Max CRA / FOV) of a maximum chief ray angle (Max CRA) to a field of view (FOV) of the folding digital camera (Max CRA / FOV) is less than 0.25 or to less than 0.15.

Description

[0001] Related Applications

[0002] This application is a divisional application of “Folded digital camera lens design”, filed on July 14, 2021, with application number 202180004567.4. This application claims priority to U.S. Provisional Patent Application No. 63 / 059,200 filed on July 31, 2020 and U.S. Provisional Patent Application No. 63 / 070,501 filed on August 26, 2020, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The invention relates to the field of digital cameras, in particular to a folding lens in the digital camera.

[0004] definition

[0005] In this application, for optical and other characteristics mentioned throughout the specification and drawings, the following symbols and abbreviations are used to represent terms known in the art:

[0006] -Total track length (TTL): The total track length measured along an axis parallel to the optical axis of a lens at a first lens element L when the system is focused to an infinite object distance. 1 The front surface S 1 A maximum distance between a point and an image sensor.

[0007] - Back focal length (BFL): The minimum distance between a point on the back surface S2N of the last lens element LN and an image sensor measured along an axis parallel to the optical axis of a lens when the system is focused to an infinite object distance.

[0008] - Effective focal length (EFL): In a lens (assembly of lens elements L1 to LN), the distance between a rear principal point P' and a rear focal point F' of the lens.

[0009] - Aperture value (f-number): The ratio of EFL to the entrance pupil diameter.

[0010] - Chief ray angle (CRA): An (image-side) chief ray is the line between the center of the exit pupil of a lens system and an image point. CRA is the angle between a chief ray and the optical axis of the lens. Here and below, we refer to image-side chief rays and CRAs in contrast to an object-side chief ray, which is the line between an object point and the center of the entrance pupil of a lens system.

[0011] The line connecting the center of the entrance pupil. - Maximum chief ray angle (Max CRA)

[0012] is the maximum chief ray angle (CRA) present in a lens system that takes into account all fields supported by the lens system. Background Art

[0013] Multi-aperture cameras (or "multi-cameras", where a "dual camera" with two cameras is an example) are becoming a standard choice for manufacturers of portable electronic mobile devices (e.g., smartphones, tablets, etc.). A multi-camera setup typically includes a wide field of view (or "angle") FOVW camera (the "wide" camera or "W" camera) and at least one additional camera, either with the same FOV (e.g., a depth assist camera), with a narrower (than FOVW) FOV (a telephoto or "tele" camera with FOVT), or with an ultra-wide field of view FOVUW (wider than FOVW, a "UW" camera).

[0014] Figure 1A and Figure 1B A known folded digital camera 100 is shown. The camera 100 includes an optical path folding element (OPFE) 102, such as a prism or a reflector, and a lens 104 having a plurality of lens elements (not shown here, but may be seen in the drawings). FIG. 2A to FIG. 2D is visible) and an image sensor 106. The lens element may be (eg FIG. 2A to FIG. 2D The lens element is symmetrical along an optical axis 108 (as shown). In other embodiments, the lens element may not be symmetrical. For example, the lens element may be cut (diced, sliced) into a non-circular shape (not shown).

[0015] At least some of the lens elements may be included in a "barrel" 110. The barrel may have a longitudinal symmetry along the optical axis 108. In FIGS. 1A to 1C, the cross-section of this barrel is circular. However, this is not mandatory and other shapes may be used, for example for hosting cut lens elements.

[0016] The path of the light from an object (not shown) to an image sensor 106 defines an optical path (see optical paths 112 and 114, which represent a portion of the optical path). The optical path folding element folds the optical path from a first optical path 112 to a second optical path 114, which is substantially parallel to the optical axis 108.

[0017] In particular, in some examples, the optical path folding element 102 is tilted at substantially 45 degrees relative to the optical axis 108. Figure 1A In the embodiment, the optical path folding element 102 may also be tilted at substantially 45 degrees relative to the optical path 102 .

[0018] In some known examples, image sensor 106 is located in an XY plane that is substantially perpendicular to optical axis 108. However, this is not limiting, and image sensor 106 may have a different orientation. For example, as described in International Published Patent Application No. WO2016 / 024192, image sensor 106 may be located in an XZ plane. In this case, an additional OPFE may be used to reflect the light toward image sensor 106.

[0019] Two cameras, such as a wide-angle camera 100 and a conventional UW camera 130, may be included in a digital camera 150 (also referred to as a dual camera). Figure 1C One possible configuration is shown in FIG. 1 . The UW camera 130 may include an aperture 132 (pointing toward the object side of the camera) and an optical lens system 134 (or "wide angle lens module") having a symmetry (and optical) axis 136 in the Y direction, and a UW image sensor 138. The UW camera includes a UW lens system configured to provide a UW image. As previously described, the UW camera has a FOV greater than W Larger field of view FOV UW For example, FOV UW can be 80 to 130 degrees, and the FOV W It can be 60 to 90 degrees. It is worth noting that in other examples, multiple wide-angle cameras and / or multiple telephoto cameras can be combined and operated in a single digital camera. The FOV of a telephoto camera T It may be, for example, 20 to 50 degrees.

[0020] "Macro-photography" mode is becoming a popular differentiator for smartphone cameras. "Macro-photography" refers to photographing an object close to the camera so that the image recorded on the image sensor is almost as large as the actual object photographed. The ratio of the image size to the object size is the object-to-image magnification M, which is defined as:

[0021]

[0022] where v is the lens-image distance defined by the distance from the second (or "rear") principal plane of the lens to the image, and u is the object-lens distance defined by the distance from the object to the first (or "front") principal plane of the lens. The minus sign (-) is usually not explicitly mentioned.

[0023] In digital single-lens reflex (DSLR), a macro image is defined as having a magnification M of about 1:1 or greater, for example, 1:1.1. In smartphones, a "macro image" may refer to an image with a magnification M of about 10:1 or even 5:1. The first smartphone modules offering macro photography capabilities have entered the consumer market, typically by using a UW camera with a relatively short EFL (e.g., 2.5 mm) to achieve very close focus.

[0024] A UW camera can focus to the close distances required for macro photography (e.g., 1.5 cm to 15 cm), but due to its small focal length and large FOV, its spatial resolution is poor. For example, consider a UW camera with a focal length of 2.5 mm. When focusing on an object at 5 cm (lens-object distance), the UW camera will have approximately M = 19:1. This is based on the thin lens equation with EFL = 2.5 mm, v = 2.6 mm, and u = 50 mm. Even when focusing as close as 1.5 cm, the M of the UW camera will be approximately 5:1. From these short object-lens distances, such as u = 5 cm or less, capturing objects in macro images can be very challenging for a user. For example, it can make framing the image very difficult, can prohibit the capture of popular macro objects such as images of living things (e.g., insects), and can introduce shadows and blur the lighting in the scene. In addition, UW cameras have a relatively large depth of field (DoF), even for macro images. The relatively large depth of field corresponds to a low degree of optical bokeh, which is a very popular effect in macro photography.

[0025] It is beneficial to have a macro camera in a mobile device to capture macro images from a larger lens-object distance (eg, 5-15 cm) with a larger object-to-image magnification ratio (eg, 1:1 to 15:1) and with a high degree of optical bokeh. Summary of the invention

[0026] In various embodiments, a folded digital camera is provided, comprising: a lens system having a lens and an image sensor, wherein the lens has N lens elements L i , an effective focal length (EFL) and a total track length (TTL), where N is greater than or equal to 6, and each lens element has a respective focal length f i , and one of the first lens elements L 1 An optical path folding element (OPFE) facing an object side is used to provide a folded optical path between an object and the lens; wherein the lens system has a focusing range covering from infinity to a minimum object distance (MIOD), and wherein the minimum object distance / the effective focal length (MIDO / EFL) is less than 20.

[0027] In various embodiments, a folded digital camera is provided, comprising: a lens system having a lens and an image sensor, wherein the lens has N lens elements L i , an effective focal length (EFL) and a total track length (TTL), where N is greater than or equal to 6, and each lens element has a respective focal length f i , and one of the first lens elements L 1 an optical path folding element (OPFE) for providing a folded optical path between an object and the lens; wherein when the folded digital camera is focused at infinity, a ratio (Max CRA / FOV) of a maximum chief ray angle (MaxCRA) to a field of view (FOV) of the folded digital camera is less than 0.25.

[0028] In some embodiments, the minimum object distance / the effective focal length (MIDO / EFL) may be less than 15, 13, 10 or even less than 7.

[0029] In some embodiments, a maximum field curvature (MFC) for any object within the focus range may be less than 50 microns.

[0030] In some embodiments, the folded digital camera may have an f-number less than 4, 3, or even less than 2.5.

[0031] In some embodiments, the lens element may be divided into two groups of lens elements by a large gap that is greater than one eighth, one seventh, or even one sixth of the total track length.

[0032] In some embodiments, the lens element can be divided into a first lens element group having an effective focal length EFL1 and a second lens element group having an effective focal length EFL2, and wherein a ratio (EFL1 / EFL2) of the effective focal length EFL1 to the effective focal length EFL2 deviates from 1 by no more than 20% or even by no more than 10%.

[0033] In some embodiments, the foldable digital camera may further include a focusing mechanism, so that the foldable digital camera can be focused based on a voice coil motor.

[0034] In some embodiments, the first lens element L 1 and a second lens element L 2 It can be made of a material with an Abbe number greater than 50.

[0035] In some embodiments, the total track length / the effective focal length (TTL / EFL) may be less than 1.5, 1.4, or even less than 1.3.

[0036] In some embodiments, a ratio (fN) of a focal length fN of the last lens element LN to the total track length N / TTL) can be less than 1.0, 0.9, 0.8, 0.75 or even less than 0.7.

[0037] In some embodiments, the maximum chief ray angle / the field of view (Max CRA / FOV) may be less than 0.2 or even less than 0.15.

[0038] In some embodiments, a maximum field curvature (MFC) for any object within the focus range may be less than 50 microns. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Non-limiting examples of the embodiments disclosed herein are described below with reference to the attached drawings listed after 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.

[0040] Figure 1A A known foldable digital camera is schematically shown in a perspective view.

[0041] Figure 1B A side view schematically shows Figure 1A of the camera. Figure 1C A known dual camera including a digital camera and an upright camera is schematically shown in a perspective view.

[0042] Figure 2A An optical lens system disclosed in this article is schematically shown.

[0043] Figure 2B Another optical lens system disclosed herein is schematically shown.

[0044] Figure 2C Yet another optical lens system disclosed herein is schematically illustrated.

[0045] Figure 2D Still another optical lens system disclosed herein focusing to infinity is schematically shown.

[0046] Figure 2E Schematically shows Figure 2D The lens system is focused to 100 millimeters (mm).

[0047] Figure 2F Schematically shows Figure 2D The lens system is focused to 50 millimeters (mm).

[0048] Figure 2G An optical lens system disclosed herein is schematically shown having a lens element cut into a non-circular shape.

[0049] Figure 2H Another optical lens system disclosed herein is schematically shown having a lens element cut into a non-circular shape.

[0050] Fig.2I Yet another optical lens system disclosed herein is schematically shown having a lens element cut into a non-circular shape.

[0051] Figure 2J Yet another optical lens system disclosed herein is schematically shown having a lens element cut into a non-circular shape.

[0052] Figure 2K Still another optical lens system disclosed herein focusing to infinity is schematically shown.

[0053] Figure 3A Two impact points IP on a plane P are shown 1 and IP 2 Orthogonal projection IP orth,1 、IP orth,2 , the plane P and FIG. 2A to FIG. 2D The optical axes of the lenses of the system are orthogonal.

[0054] Figure 3B Two impact points IP on a plane P are shown 3 and IP 4 Orthogonal projection IP orth,3 、IP orth,4 , the plane P and FIG. 2A to FIG. 2D The optical axes of the lenses of the system are orthogonal.

[0055] Figure 4 The definition of clear height is provided graphically.

[0056] Figure 5 A definition of clear aperture is provided graphically.

[0057] Figure 6 Provides lens element L i Diameter H Li A graphic illustration of .

[0058] Figure 7 An exploded view of the lens elements is shown, illustrating the lens element width W L and height H L . DETAILED DESCRIPTION

[0059] In the following detailed description, many specific details are set forth to provide a thorough understanding. However, those skilled in the art will appreciate that the subject matter disclosed herein can be practiced without these specific details. In other cases, well-known methods are not described in detail to avoid obscuring the subject matter disclosed herein.

[0060] FIG. 2A to FIG. 2J Various lens systems disclosed herein are shown. FIG. 2A to FIG. 2J All lens systems in the can be included in e.g. Figure 1A and Figure 1B A foldable digital camera is shown in FIG.

[0061] Figure 2AAn optical lens system disclosed herein and referenced 200 is schematically illustrated. Lens system 200 includes a lens 204, an optical element 206, and an image sensor 208. Lens system 200 is shown as a ray trace. Optical element 206 may be, for example, an infrared (IR) filter and / or a glass image sensor dust cover. Light rays (after they are reflected by prism 202) pass through lens 204 and form an image on image sensor 208. Figure 2A Three fields are shown, each with three rays: the upper marginal ray, the lower marginal ray, and the principal ray. Figure 2A In the example of FIG. 2 , the light rays pass through optical element 206 before striking image sensor 208. However, this is not limiting, and in some examples, optical element 206 is not present. That is, the optical element may be optional in some designs.

[0062] The lens 204 includes a plurality of N lens elements L i , where "i" is an integer between 1 and N. In lens system 200, N is equal to 6. However, this is not limiting, and a different number of lens elements may be used. According to some examples, N is equal to or greater than 5. For example, N may be equal to 5, 6, 7, 8, 9, or 10. L 1 is the lens element closest to the object (prism) side, L N The lens element closest to the image side, i.e., the side where the image sensor is located. This order applies to all lenses and lens elements disclosed herein. i It can be used, for example, as a lens element of a camera similar to the camera 100. The N lens elements are axisymmetric along an optical (lens) axis 210. Each lens element L i including a respective front surface S 2i-1 (index "2i-1" is the number of the front surface) and a respective rear surface S 2i (The index "2i" is the number of the rear surface.) This numbering convention is used throughout the specification. Alternatively, as is done in this specification, the lens surface is labeled "S k ”, where k is from 1 to 2N. In some cases, the front surface and the back surface may be aspherical. However, this is not limiting.

[0063] As used herein, the term "front surface" of each lens element refers to the surface of a lens element located near the camera entrance (camera object side), and the term "back surface" refers to the surface of a lens element located near the image sensor (camera image side).

[0064] As described below, each surface Sk (For 1≤k≤2N) define a clear height value CH(S k ) and a clear aperture value CA(S k ). CA(S k ) and CH(S k ) defines each surface S of each lens element k Optical properties of CH. Figure 4 is defined by CA, while CA is the reference Figure 5 To be defined.

[0065] In addition, a height H is defined for each lens element Li Li (for 1≤i≤N). For each lens element L i , H Li corresponds to the lens element L measured along an axis perpendicular to the optical axis of the lens element i For a given lens element, the respective H Li is greater than or equal to the CH and CA of the front and back surfaces of the given lens element. In general, for an axisymmetric lens element, H Li is the lens element L i The diameter, such as Figure 6 As shown. Usually, for an axisymmetric lens element, H Li =max{CA(S 2i-1 ),CA(S 2i )}+a mechanical component size. Usually, in lens design, the mechanical component size is defined to have no effect on the optical properties of the lens. Therefore, a lens element L is defined i The optical height H of the optically active region 602 is opt,i (corresponding to the CA value) and the lens H of the entire lens area 604 Li The entire lens area 604 covers an optically active area and an optically inactive area. The mechanical parts and their characteristics are defined as follows. Li The contribution is typically 200 to 1000 micrometers (μm).

[0066] In lens system 200, some surfaces of the lens element are convex and some are concave. Figure 2A The representation is not 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.

[0067] like Figure 3A , Figure 3B and Figure 4 As shown, through a surface S k Each ray of light strikes an impact point IP on this surface. 1 Entering the optical lens system 200 and passing through the surface S 2 To the surface S 2N Some light can hit any surface S k , but cannot / will not reach the image sensor 208. For a given surface S k , only the light that can form an image on the image sensor 208 is considered. k ) is defined as the distance between two closest possible parallel lines, see Figure 4 Lines 400 and 402 are located on a plane P that is orthogonal to the optical axis of the lens element. Figure 3A and Figure 3B In the representation, the plane P is parallel to the plane XY and is orthogonal to the optical axis 302, so that the orthogonal projection IP of all impact points IP on the plane P orth Located between two parallel lines.

[0068] CH(S k ) does not depend on the object currently being imaged, as it refers to light that "can" form an image on the image sensor. Thus, even if the object currently being imaged is located in a black background that does not generate light, the definition does not refer to such a black background, as it refers to any light that "can" reach the image sensor to form an image (e.g., light emitted by a background that emits light, as opposed to a black background).

[0069] Figure 3A Two impact points IP on plane P are shown 1 and IP 2 Orthogonal projection IP orth,1 、IP orth,2 , the plane P is orthogonal to the optical axis 302. For example, Figure 3A In the representation of k It is convex.

[0070] Figure 3B Two impact points IP on plane P are shown 3 and IP 4 Orthogonal projection IP orth,3 、IP orth,4 For example, in Figure 3B In the representation of k It is concave.

[0071] exist Figure 4 In the example, a surface S on plane P kThe orthogonal projection IP of all impact points IP orth Located between parallel lines 400 and 402 .

[0072] Notice Figure 5 According to the subject matter of the present disclosure, for each given surface S k (for 1≤k≤2N), a clear aperture CA(S k ) is defined as the diameter of a circle, wherein the circle is located in a plane P orthogonal to the optical axis 108 and surrounds all orthogonal projections IP of all impact points on the plane P orth As mentioned above, about CH(S k ), CA(S k ) also does not depend on the object currently being imaged. Figure 5 As shown, the circumscribed orthogonal projection IP of all impact points IP on plane P orth is a circle 500. The diameter of the circle 500 defines CA(S k ).

[0073] Tables 1 to 3 give Figure 2A Detailed optical data and surface data for examples of lens elements in FIG. The values ​​provided for these examples are purely illustrative, and other values ​​may be used according to other examples.

[0074] The surface types are defined in Table 1. The coefficients of the surfaces are defined in Table 2. The surface types are:

[0075] a) Plano: flat surface, no curvature

[0076] b) Q type 1 (QT1) surface sag formula:

[0077]

[0078] where {z,r} are standard cylindrical polar coordinates, c is the paraxial curvature of the surface, k is the conic parameter, and r norm is usually half the clear aperture of the surface, and A n are the polynomial coefficients in the lens data table. The Z axis is positive toward the image. The value of CA is given as a clear aperture radius, i.e. CA / 2. The reference wavelength is 555.0 nanometers (nm). Except for the refractive index ("Index") and Abbe number (Abbe#), the unit is millimeter (mm). Each lens element L i have a respective focal length f i, as shown in Table 1. The field of view FOV is given as half field of view (half FOV, HFOV). The definitions of surface type, Z axis, CA value, reference wavelength, unit, focal length and HFOV apply to Tables 1 to 17.

[0079]

[0080] Table 1

[0081]

[0082] Table 2

[0083] Table 3 provides details on the variation of the characteristics of the lens system 200 with object-lens distance. The object-lens distance is defined as the distance from the object to the first principal plane of the lens.

[0084] Table 4 provides details about the maximum (image-side) CRA of lens system 200. The maximum chief ray angle (maximum CRA) and half field of view (Half FOV, HFOV) are given for several object-lens distances ("object"). The data refers to a 3.5 mm region corresponding to an edge of the image sensor (i.e., the upper end of the sensor diagonal).

[0085] In order to achieve a small maximum CRA value, the last lens element L N The focal length f N Less than the total track length (TTL) of the lens. The TTL of lens 204 is 18 mm. For lens 204, f 6 =12.05 mm, f N / TTL ratio = 0.67.

[0086]

[0087] Table 3

[0088]

[0089] Table 4

[0090] The focusing range of the lens system 200 is from infinity to 100 mm. The focusing range of a lens system is defined as all object-lens distances that can be focused by a camera mechanism that controls the distance between the lens and the image sensor. That is, for each object within the focusing range, the focusing mechanism can set a specific lens-image sensor distance to provide maximum contrast for the image of the object. Maximum contrast means that for lens-image sensor distances outside the specific lens-image sensor distance, the contrast of the object will be reduced. The minimum object distance (MIDO) is defined as the lower limit of the focusing range, that is, MIOD is the minimum object-lens distance that the lens system can focus on. For the lens system 200, MIOD is 100 mm. The lens system 200 can focus continuously from infinity to 100 mm, that is, any focus position between infinity and 100 mm (and any magnification between 0 and -0.153) can be achieved.

[0091] To focus using lens 204, all lens elements move together. To change the focus from infinity to 100 mm, a lens movement of 2.272 mm ("lens stroke") is required. To move the lens, an actuator known in the art, such as a voice coil motor (VCM), can be used. A Hall sensor-magnet geometry for long-stroke linear position sensing is described in U.S. Provisional Patent Application No. 63,059,200, which is necessary to support VCMs with large strokes (e.g., 2 mm or greater). At MIOD, lens system 200 achieves a magnification of -0.153, corresponding to an object-image ratio of approximately 6.5:1. The HFOV decreases from 13.25 degrees when focused at infinity to 12.34 degrees when focused at MIOD.

[0092] For any object within the focus range, lens system 200 has a maximum field curvature (MFC) of less than 50 micrometers (μm). MFC can be defined as follows: when a lens such as lens 204 is placed at a distance v from a planar image sensor such as image sensor 208, image points on the optical axis will be in perfect focus, but image points outside the optical axis will not be focused on the image sensor, but will be focused at a distance v' less than v, where v' is less than the MFC for all image points.

[0093] For example, a lens of lens 204 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 204, the focusing group includes lens element L 1 , L 2 , L 3 and L 4 The CRA correction group includes lens element L 4 and L 5 The focus group and the CRA correction group are spatially separated from each other by a large gap (BG) of 3.954 mm. All lens elements of G1 together have EFL1 = 14.71 mm. All lens elements of G2 together have EFL2 = 13.55 mm.

[0094] exist Figure 2G , and in order to achieve a folded lens system having both a low f / # and a low lens height, the lens element is cut into a non-circular shape ("D-cut"). The cut lens element can be obtained by cutting the large lens element of lens 204 to a height (in the Y direction) of, for example, 6 mm, so that the lens is now a cut lens 204-C. That is, the height H Li >6mm lens 204 (i.e. L 1 , L 5 and L 6 ) of the lens element L i The lens element is cut in the Y direction. The cutting is done symmetrically, i.e. the top of the cut (by Figure 2A The size of the cut bottom (defined by the larger Y value in Figure 2A The cut lens elements in 204-C do not have the circular symmetry of lens element 204; their width is greater than their height, i.e., W Li >H Li (See Figure 7 ). Height H Li Lens element L of lens 204 ≤ 6 mm i No changes. As for cutting, cutting lens element L 1 , L 5 and L 6 Having a larger CA but still a lower CH. This is beneficial in a folded lens design where a lens height H LThe height of the camera can be determined, where the camera height is usually limited by a height of the host device. A folded lens with large CA and low CH is advantageous to have a low f / # folded lens that is compatible with the height restrictions of, for example, a smartphone. Lens element L 2 , L 3 and L 4 The CA can be oriented in any direction, such as the Y direction. In the cut design, the lens element L 1 , L 5 and L 6 The CA is oriented in the X direction (not visible here).

[0095] By cutting the lens element, light is lost at the extreme rays, but no light loss is expected for the central rays. The light loss is given as the percentage of light penetration through the image plane at an image sensor border at coordinates (X,Y) = (0,2.1 mm), i.e., 2.1 mm upward from the optical axis:

[0096] - Infinity: 92.49%

[0097] -1 meter (m): 92.22

[0098] -0.5 meters (m): 91.94%

[0099] -20 cm: 91.01%

[0100] -10 cm: 89.43%

[0101] In other embodiments, it may be possible to cut only one or only two lens elements L i , that is, there may be W Li >H Li In another embodiment, more than three lens elements L may be cut. i , that is, there may be W Li >H Li In another embodiment, it is possible to cut all lens elements L i , that is, it may have W Li >H Li In another embodiment, a cut lens, i.e., a height H , can be achieved by cutting the large lens element of the lens 204 into a height (in the Y direction) of, for example, 6.5 mm, 5 mm, or 4 mm. Li >6.5 mm, 5 mm or 4.5 mm lens element L i Can be cut into 6.5mm, 5mm or 4.5mm respectively.

[0102] Now notice Figure 2B, which schematically depicts another optical lens system disclosed herein and numbered 220. The lens system 220 includes a lens 204' having a plurality of lens elements, an optical element 206 (optional), and an image sensor 208'. Ray tracing such as Figure 2A Detailed optical and surface data are given in Tables 5, 6, 7, and 8. Table 8 provides details about the maximum CRA of lens system 220. The symbols and fields are the same as Table 4.

[0103] Figure 2B Three fields are shown, each with three rays: an upper marginal ray, a lower marginal ray, and a principal ray.

[0104] The focusing range of the lens system 220 is from infinity to 100 mm, ie, the MIOD is 100 mm.

[0105] To focus using lens 204', all lens elements move together. To change the focus from infinity to 100 mm, a lens travel of 2.237 mm is required. To move the lens, an actuator known in the art, such as a VCM, can be used. At the MIOD, the lens system 210 achieves a magnification of -0.15, corresponding to an object-image ratio of approximately 6.7:1. The HFOV decreases from 13.29 degrees when focused at infinity to 12.51 degrees when focused at the MIOD. Any focus position between infinity and 100 mm (and any magnification between 0 and -0.15) can be achieved. For any object within the focus range, the lens system 220 has a maximum field curvature (MFC) of less than 50 microns.

[0106] The lens 204' can be divided into two groups, a first focusing group including lens elements L 1 , L 2 , L 3 , L 4 and L 5 , and a second CRA correction group includes L 6 and L 7 The focus group and the CRA correction group are spatially separated from each other by a large gap of 4.96 mm. All lens elements of G1 together have EFL1 = 14.08 mm, and all lens elements of G2 together have EFL2 = 13.94 mm. The TTL of lens 204' is 18 mm.

[0107] Figure 2H 2 is an embodiment of a lens system having a D-cut lens 204'-C numbered 260 based on the lens 204'. Figure 2G The light loss is given as the percentage of light penetration at coordinates (X,Y) = (0,2.1 mm):

[0108] - Infinity: 92.33%

[0109] -1 meter (m): 92.07%

[0110] -0.5m: 91.75%

[0111] -20 cm: 90.76%

[0112] -10 cm: 89.11%

[0113] The D-cut lens 204'-C can be obtained by cutting the large lens element of the lens 204' into a height (in the Y direction) of, for example, 6 mm, that is, a height H Li >6 mm lens element 204' (ie L 1 , L 6 and L 7 ) can be cut to 6 mm. In other embodiments, a cut lens, i.e., a height H , can be achieved by cutting the large lens element of the lens 204' to a height (in the Y direction) of, for example, 6.5 mm, 5 mm, or 4 mm. Li >6.5 mm, 5 mm or 4.5 mm lens element L i Can be cut into 6.5mm, 5mm or 4.5mm respectively. For details on cutting lenses, refer to Figure 2A Description.

[0114] Table 5

[0115]

[0116]

[0117] Table 6

[0118]

[0119] Table 7

[0120]

[0121] Table 8

[0122] Figure 2C Another optical lens system disclosed herein and numbered 230 is schematically depicted. The lens system 230 includes a lens 204", an optical element 206 (optional) and an image sensor 208. Ray tracing such as FIG. 2A to FIG. 2B Detailed optical and surface data are given in Tables 9, 10, 11, and 12. Table 12 provides details about the maximum CRA of the lens system 220. The symbols and fields are the same as Table 4.

[0123] Figure 2C 3 fields are shown, each with 3 rays: upper marginal ray, lower marginal ray and chief ray. The focusing range of lens system 230 is from infinity to 76.4 mm, i.e., the MIOD is 76.4 mm. To focus using lens 204', all lens elements move together. To change the focus from infinity to 100 mm, a lens travel of 2.881 mm is required. To move the lens, an actuator known in the art (e.g., a VCM) can be used. At the MIOD, lens system 230 achieves a magnification of -0.195, corresponding to an object-image ratio of about 5.1:1. The HFOV decreases from 13.29 degrees when focused at infinity to 12.52 degrees when focused at the MIOD. Any focus position between infinity and 76.4 mm (and any magnification between 0 and -0.195) can be achieved. For any object in the focusing range, lens system 230 has an MFC of less than 50 microns.

[0124] The lens 204" can be divided into two groups, a first focusing group including lens elements L 1 , L 2 , L 3 , L 4 and L 5 , and a second CRA correction group includes L 6 , L 7 and L 8 The focus group and the CRA correction group are spatially separated from each other by a large gap of 3.839 mm. All lens elements of G1 together have EFL1 = 13.50 mm, and all lens elements of G2 together have EFL2 = 11.85 mm. The TTL of lens 204" is 18 mm.

[0125] Fig.2I An embodiment of a lens system having a cut lens 204"-C numbered 270 based on lens 204" is shown. Figure 2G The light loss is given as the percentage of light penetration at coordinates (X,Y) = (0,2.1 mm):

[0126] - Infinity: 93.21%

[0127] -1 meter (m): 92.99%

[0128] -0.5 meters (m): 92.74%

[0129] -20 cm: 92.01%

[0130] -7.64 cm: 85.82%

[0131] 204"-C can be obtained by cutting the large lens element of lens 204" to a height (in the Y direction) of, for example, 6 mm. Height H Li >6mm lens 204" lens element (i.e. L 1 , L 2 , L 6 , L 7 and L 8 ) is cut to 6 mm. In other embodiments, a cut lens can be achieved by cutting the large lens element of the lens 204" to a height (in the Y direction) of, for example, 6.5 mm, 5 mm, or 4 mm. For details on the cut lens, refer to Figure 2A Description.

[0132]

[0133]

[0134] Table 9

[0135]

[0136] Table 10

[0137]

[0138] Table 11

[0139]

[0140] Table 12

[0141] Now notice Figures 2D to 2F , which is exemplarily another optical lens system disclosed herein and numbered 240. The lens system 240 includes a lens 204'', an optical element 206 (optional) and an image sensor 208''. Ray tracing such as FIG. 2A to FIG. 2C Detailed optical and surface data are given in Tables 13, 14, 15, 16, and 17. Table 17 provides details on the maximum CRA of lens system 240. The symbols and fields are the same as Table 4. Figures 2D to 2F Three fields are shown, each with three rays: an upper marginal ray, a lower marginal ray, and a principal ray.

[0142] Figure 2D shows lens system 240 focused to infinity ("Configuration A"), Figure 2E A lens system 240 is shown focused to 100 mm ("Configuration B"), and Figure 2FLens system 240 is shown focused to 50 mm ("Configuration C"). Surface 0 in Table 15 gives the object-lens distance at which it is focused. The focusing range of lens system 240 is from infinity to 50 mm, ie, the MIOD is 50 mm.

[0143] The lenses 204'' are divided into two groups that can move relative to each other for focusing. A first lens group ("G1") includes lens elements L 1 and L 2 , and a second lens group ("G2") including L 3 , L 4 , L 5 and L 6 . The large gap between G1 and G2 is reduced from 2.625 mm when focused to infinity to 1.946 mm when focused to 100 mm and 1.303 mm when focused to 50 mm (see surface #5 in Table 15). To focus, lens 204'" also moves as a unit, causing the BFL to change (see surface #13 in Table 15).

[0144] To move the lenses, an actuator (e.g., VCM) may be used. At the MIOD, the lens system 240 achieves a magnification of -0.40, corresponding to an object-image ratio of approximately 2.5:1. The HFOV decreases from 13.1 degrees when focused to infinity to 9.3 degrees when focused to the MIOD. Any focus position between infinity and 50 mm (and any magnification between 0 and -0.4) may be achieved.

[0145] For any object within the focus range, lens system 240 has an MFC of less than 50 microns. All lens elements of G1 together have EFL1 = 38.61 mm, and all lens elements of G2 together have EFL2 = 15.36 mm. The TTL of lens 204'" is 15.8 mm.

[0146] Figure 2J An embodiment of a lens system having a cut lens 204"'-C numbered 280 based on lens 204"' is shown. Figure 2G The light loss is given as the percentage of light penetration at coordinates (X,Y) = (0,2.1 mm):

[0147] - Infinity: 94.58%

[0148] -0 cm: 91.53%

[0149] -5 cm: 91.02%

[0150] The cut lens 204"'-C, i.e., the height H is obtained by cutting the large lens element of the lens 204"' into a height of 6 mm (in the Y direction). Li >6mm lens 204"' lens element (i.e. L 1 , L 2 , L 5 and L 6 ) is cut to 6 mm. In other embodiments, a cut lens can be achieved by cutting the large lens element of the lens 204'' to a height (in the Y direction) of, for example, 6.5 mm, 5 mm or 4 mm.

[0151]

[0152] Table 13 for details on cutting lenses, refer to Figure 2A Description.

[0153]

[0154] Table 14

[0155]

[0156] Table 15

[0157]

[0158] Table 16

[0159]

[0160] Table 17

[0161]

[0162] Table 18

[0163] Table 18 shows an overview of the EFLs of all lens elements for G1 and G2, and the EFL1 / EFL2 ratios for lens system embodiments 200, 220, 230, 240, and 290, respectively.

[0164] Figure 2K Another optical lens system disclosed herein and numbered 290 is schematically depicted. Lens system 290 includes a lens 204"" having a plurality of lens elements, optical element 206 (optional), and image sensor 208. Ray tracing such as Figure 2A Detailed optical and surface data are given in Tables 19, 20, 21 and 22.

[0165] The focusing range of the lens system 290 is from infinity to 52 mm (MIOD=52 mm).

[0166] To focus using lens 204", all lens elements move together. To change focus from infinity to 52 mm, 4.507 mm of lens travel is required. At the MIOD, the lens system 290 achieves a magnification of -0.29, corresponding to an object-image ratio of approximately 3.4:1. The HFOV decreases from 9.57 degrees when focused at infinity to 8.52 degrees when focused at the MIOD. Any focus position between infinity and 52 mm (and any magnification between 0 and -0.29) can be achieved. For any object within the focus range, the lens system 290 has an MFC of less than 50 microns.

[0167] The lens 204"" can be divided into two groups, a first focusing group including lens elements L 1 , L 2 , L 3 , L 4 and L 5 , and a second CRA correction group includes L 6 , L 7 and L 8 The focus group and the CRA correction group are spatially separated from each other by a large gap of 3.974 mm. All lens elements of G1 together have EFL1 = 14.1 mm, and all lens elements of G2 together have EFL2 = 12.3 mm. The TTL of lens 204"" is 18.6 mm.

[0168] Some embodiments may include a cut lens based on lens 204". The cut lens may be achieved by cutting the large lens element of the lens 204" to a height (in the Y direction) of, for example, 6.5 mm, 5 mm, or 4 mm. For details on the cut lens, refer to Figure 2A Description.

[0169]

[0170] Table 19

[0171]

[0172] Table 20

[0173]

[0174]

[0175] Table 20 (continued)

[0176]

[0177] Table 21

[0178]

[0179] Table 22

[0180] According to some examples, at least a portion of the lens element may have a non-circular cross-sectional shape (profile) (in plane XY, which is orthogonal to the optical lens system and generally coincident with the optical axis). In particular, for example Figure 7 A lens barrel 700 is shown carrying lens elements 702, at least some of which may have a width W Li (measured along the X axis), which is greater than their height H Li (measured along the Y axis). The lens barrel 700 also includes a barrel wall (or periphery) 704. The height H Li The lens element may correspond to the total height of the lens element (including the mechanical portion). In some embodiments, a lens element in lens barrel 700 may have symmetry along axis Y and / or along axis X. For example, a non-circular lens barrel of 700 may be formed based on the cut lens of a lens such as lens 204-C. Figure 7 As shown, the height of a lens barrel may be only slightly higher than the lens element with the largest height in the lens. For example, a lens barrel may be 0 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.

[0181] According to some examples, W Li Basically greater than H Li (For example, at least equal to or greater than 20%, these values ​​are not limiting). In some examples, W Li Can be compared to H Li Take the lens element L8 of the folded lens 204' as an example: L8 H L8 32% larger.

[0182] It should be understood that, for the sake of clarity, certain features of the currently disclosed subject matter described in the context of separate embodiments may also be provided in combination in a single embodiment. Conversely, for the sake of brevity, various features of the currently disclosed subject matter described in the context of a single embodiment may also be provided separately or in any suitable sub-combination.

[0183] In addition, for the sake of clarity, the term "substantially" is used herein to imply the possibility of values ​​varying within an acceptable range. According to one example, the term "substantially" used herein should be interpreted as implying a 10% variation that may be above or below any specified value. According to another example, the term "substantially" used herein should be interpreted as implying a 5% variation that may be above or below any specified value. According to a further example, the term "substantially" used herein should be interpreted as implying a possible variation of up to 2.5% above or below any specified value.

[0184] Unless otherwise stated, the use of the expression "and / or" between the last two members of a list of options for selection indicates that selection of one or more of the listed options is appropriate and can be made.

[0185] It should be understood that where the claims or specification refer to "a" or "an" element, such reference should not be interpreted as there being only one of the element.

[0186] All references mentioned in this specification are incorporated by reference in their entirety into this specification to the same extent as if each individual reference was specifically and individually indicated to be incorporated by reference herein. In addition, citation or identification of any reference in this application should not be construed as an admission that such reference is available as prior art to the present disclosure.

Claims

1. A camera, characterized in that: The camera comprises: A lens system comprises a lens and an image sensor, wherein the lens comprises N lens elements L i , an effective focal length (EFL) and a total track length (TTL), where N is greater than or equal to 6, and each lens element has a respective focal length f i , and wherein a first lens element L1 faces an object side; and an optical path folding element (OPFE) for providing a folded optical path between an object and the lens; wherein the image sensor has a sensor diagonal (SD); wherein the lens system has a focusing range covering from infinity to a minimum object distance (MIOD); wherein the minimum object distance / the effective focal length (MIOD / EFL) is greater than or equal to 3.33 and less than 20; The sensor diagonal / the effective focal length (SD / EFL) is greater than 0.3 and less than 0.

7.

2. The camera according to claim 1, characterized in that: The sensor diagonal / the effective focal length (SD / EFL) is greater than 0.4 and less than 0.

5.

3. The camera according to claim 1, characterized in that: The minimum object distance / the effective focal length (MIOD / EFL) is less than 15.

4. The camera according to claim 1, characterized in that: The minimum object distance / the effective focal length (MIOD / EFL) is less than 10.

5. The camera according to claim 1, characterized in that: When the camera is focused at infinity, a ratio (Max CRA / FOV) of a maximum chief ray angle (Max CRA) to a field of view (FOV) of the camera is greater than or equal to 0.03 and less than or equal to 0.

25.

6. The camera according to claim 5, characterized in that: The maximum chief ray angle / the field of view (Max CRA / FOV) is less than or equal to 0.

2.

7. The camera according to claim 1, characterized in that: A maximum field curvature (MFC) for any object within the focus range is less than 50 microns.

8. The camera according to claim 1, characterized in that: The effective focal length is between 10 mm and 30 mm.

9. The camera according to claim 1, characterized in that: The effective focal length is between 12.5 mm and 17.5 mm.

10. The camera according to claim 1, characterized in that: The first lens element L1 and a second lens element L2 form an object side lens group.

11. The camera according to claim 1, characterized in that: The first lens element L1, a second lens element L2, a third lens element L3 and a fourth lens element L4 form an object side lens group.

12. The camera according to claim 1, characterized in that: The first lens element L1, a second lens element L2, a third lens element L3, a fourth lens element L4 and a fifth lens element L5 form an object side lens group.

13. The camera according to claim 1, characterized in that: The camera has an aperture value (f / #) less than 3.

5.

14. The camera according to claim 13, characterized in that: The aperture value (f / #) is less than 2.

75.

15. The camera according to claim 13, characterized in that: The aperture value (f / #) is less than 2.

5.

16. The camera according to claim 1, characterized in that: The lens element is divided into two lens element groups by a gap greater than one eighth of the total track length.

17. The camera of claim 1, wherein: The lens element is divided into two lens element groups by a gap greater than one sixth of the total track length.

18. The camera of claim 1, wherein: The lens element is divided into a first lens group G1 and a second lens group G2, wherein the first lens group G1 and the second lens group G2 are separated by a gap, and wherein the first lens group G1 and the second lens group G2 can move relative to each other for focusing.

19. The camera according to claim 18, characterized in that: For focusing, the second lens group G2 may move away from the image sensor and toward the first lens group G1 .

20. The camera of claim 18, wherein: For focusing, both the first lens group G1 and the second lens group G2 are movable relative to the image sensor.

21. The camera of claim 20, wherein: For focusing, a relative moving distance between the first lens group G1 and the second lens group G2 is smaller than a relative moving distance between the second lens group G2 and the image sensor.

22. The camera of claim 1, wherein: One or more of the lens elements is a cut lens element.

23. The camera of claim 1, wherein: The lens element is divided into a first lens element group having a first effective focal length EFL1 and a second lens element group having a second effective focal length EFL2, and wherein a ratio (EFL1 / EFL2) of the first effective focal length EFL1 to the second effective focal length EFL2 deviates from 1 by no more than 20%.

24. The camera of claim 1, wherein: The camera also includes a voice coil motor based focusing mechanism for focusing the camera.

25. The camera of claim 1, wherein: The total track length / the effective focal length (TTL / EFL) is less than 1.

25.

26. The camera of claim 1, wherein: The last lens element L N The focal length f N A ratio of the focal length to the effective focal length satisfies the focal length / the effective focal length (f N / EFL) is less than 1.

27. A camera as claimed in any one of claims 1 to 26, characterised in that: The camera is included in a mobile device.

28. The camera of claim 27, wherein: The mobile device is a smart phone.

Images