PATENT DOCUMENT

Publication Number: US-12000997-B2
Application Number: US-202117399856-A
Country: US
Kind Code: B2

Title: Zoom lens and imaging apparatus

Abstract:
A lens system provides a zoom function (variable magnification) in a low profile camera (lens system height less than or equal to 6 mm), which may be in a cellular phone. The lens system includes at least three movable lens groups that are movable along a common optical axis. Each of the three movable lens groups is coupled to a corresponding actuator. Responsive to a request for a change in focal length or magnification, a controller sends a corresponding signal to each of the actuators that move the corresponding lens group by a corresponding distance in a corresponding direction. The various movable lens groups may be moved by different distances and in different directions of movement. An f-number of the lens system is less than f/3.0. Focusing of an image cast onto an image sensor is accomplished by adjusting the position along the optical axis of one of the movable lens groups.

Claims:
What is claimed is: 
     
       1. An optical system, comprising:
 a light folding element configured to reflect received light onto an optical axis; 
 at least three lens groups, each lens group comprising one or more respective lens elements, each lens group positioned along the optical axis so as to receive and refract at least a portion of the light directed along the optical axis; and 
 at least three actuators, each actuator coupled with a respective one of the lens groups, each of the actuators configured to:
 receive a corresponding signal indicating a corresponding direction of displacement along the optical axis for the respective lens group; and 
 in response to receipt of the corresponding signal, move the respective lens group along the optical axis by a corresponding displacement in the corresponding direction of displacement, 
 wherein to increase a focal length of the optical system, the at least three actuators are configured to:
 move a particular one of the at least three lens groups along the optical axis in a direction toward an image plane toward which the received light is directed; and 
 move two others of the at least three lens groups along the optical axis in another direction that is away from the image plane; 
 
 
 wherein an f-number of the optical system is less than f/3.0. 
 
     
     
       2. The optical system of  claim 1 , wherein a first one of the at least three actuators is configured to displace one of the lens groups in one direction along the optical axis while two others of the at least three actuators displace two others of the at least three lens groups in an opposite direction along the optical axis. 
     
     
       3. The optical system of  claim 1 , wherein to decrease a focal length of the optical system, the at least three actuators are configured to:
 move a particular one of the at least three lens groups along the optical axis in a direction away an image plane toward which the received light is directed; and 
 move two others of the at least three lens groups along the optical axis in another direction that is toward the image plane. 
 
     
     
       4. The optical system of  claim 1 , wherein the light folding element comprises a mirror, or a prismatic element having a refractive index greater than or equal to 1.7. 
     
     
       5. The optical system of  claim 1 , wherein the optical system has a focal length C at a maximum focal length state associated with the optical system, and one of the lens groups that is closer to the light folding element along the optical axis than others of the lens groups, has a negative refractive power and a focal length B and satisfies a relationship that a ratio of the focal length B to the focal length C, (B/C), is between −0.6 and −0.1. 
     
     
       6. The optical system of  claim 1 , wherein the optical system has a 35 mm equivalent focal length of at least 78 millimeters and less than or equal to 130 millimeters. 
     
     
       7. The optical system of  claim 1 , the at least three lens groups comprising, in order along the optical axis:
 a first lens group comprising a fixed lens having a positive refractive power and fixed in position on the optical axis; 
 a second lens group comprising one or more lenses and having a negative refractive power and movable along the optical axis; 
 a third lens group comprising one or more lenses and having a positive refractive power, wherein the third lens group is fixed in position along the optical axis; 
 a fourth lens group comprising one or more lenses and having positive refractive power, wherein the fourth lens group is movable along the optical axis; 
 a fifth lens group comprising one or more lenses and having negative refractive power, wherein the fifth lens group is movable along the optical axis; and 
 a sixth lens group comprising one or more lenses and having a positive refractive power, wherein the sixth lens group is fixed in location along the optical axis. 
 
     
     
       8. The optical system of  claim 1 , wherein the optical system is configured to provide a 35 mm equivalent focal length between 78 mm and 130 mm. 
     
     
       9. The optical system of  claim 1 , wherein the f-number of the optical system is between f/2.3 and f/2.9. 
     
     
       10. A method, comprising:
 receiving, by a controller, a request to change a focal length associated with an optical system comprising a light folding element and a plurality of lens groups positioned serially on an optical axis; and 
 responsive to the request, sending respective signals from the controller to each of at least three actuators, each of the at least three actuators configured to move a respective lens group of the optical system along the optical axis responsive to receipt of the respective signal that results in changing the focal length associated with the optical system, sending the respective signals comprising:
 sending a first signal to a first actuator of the at least three actuators to move the respective lens group for the first actuator in a first direction along the optical axis; 
 sending a second signal to a second actuator of the at least three actuators to move the respective lens group for the second actuator in a second direction that is opposite to the first direction along the optical axis; and 
 sending a third signal to a third actuator of the at least three actuators to move the respective lens group for the third actuator in the second direction along the optical axis, 
 
 wherein an f-number of the optical system is less than f/3.0. 
 
     
     
       11. The method of  claim 10 , further comprising:
 receiving a request at the controller to focus an output image onto an image plane resulting from light refracted by the optical system; and 
 responsive to the request, sending a corresponding focus signal to one of the at least three actuators to change a position of the respective lens group that is closer to the image plane of the at least three lens groups configured to be moved by a respective actuator. 
 
     
     
       12. A camera, comprising:
 an image sensor configured to sense light impinging on a surface of the image sensor that intersects an optical axis; 
 an optical system comprising:
 a light-folding element configured to receive light at an object side of the lens system along an input axis, and to reflect the received light along the optical axis; and 
 at least three lens groups located along the optical axis between the light-folding element and the image sensor and configured to refract the received light that has been reflected along the optical axis for an image, 
 wherein the optical system has a focal length C at a maximum magnification, one of the lens groups has a focal length B, and wherein a ratio of the focal length B to the focal length C, (B/C), is within a range of values from −0.6 to −0.1; 
 wherein an f-number of the optical system is less than f/3.0; 
 
 at least three actuators each configured to move a respective one of the at least three lens groups; and 
 a controller configured to receive a request to change a focal length of the optical system from a current focal length to a requested focal length, and in response to the request, send a plurality of different commands, each command sent to a corresponding actuator of the at least three actuators; 
 wherein each actuator of the at least three actuators is configured to receive a respective one of the plurality of commands and responsive to receipt of the respective command:
 move the respective one of the lens groups along the optical axis in a corresponding direction of movement indicated in the corresponding command. 
 
 
     
     
       13. The camera of  claim 12 , wherein the requested focal length is greater than the current focal length and the controller, in response to the received request, is configured to:
 send a corresponding signal to one of the actuators, to move the respective lens group along the optical axis in a particular direction that is toward an image plane toward which the received light is directed; and 
 send corresponding signals to each of two others of the actuators to move respective ones of the lens groups in an opposite direction that opposite to the particular direction. 
 
     
     
       14. The camera of  claim 12 , wherein the requested focal length is less than the current focal length and the controller, in response to the received request, is configured to:
 send a corresponding signal to one of the actuators to move the respective lens group along the optical axis in a particular direction that is away from an image plane toward which the received light is directed; and 
 send corresponding signals to each of two others of the actuators to move respective ones of the lens groups in an opposite direction that is opposite to the particular direction. 
 
     
     
       15. The camera of  claim 12 , wherein one of the lens groups comprises a lens with positive refractive power and that has an Abbe number that is greater than 60. 
     
     
       16. The camera of  claim 12 , wherein a height of the optical system, measured on an axis perpendicular to the optical axis, is less than or equal to 6 millimeters. 
     
     
       17. The camera of  claim 12 , the at least three actuators configured to move the at least three lens groups along the optical axis that causes a variation in 35 mm equivalent focal length between 78 mm and 130 mm.

Description:
This application claims benefit of priority to U.S. Provisional Application Ser. No. 63/064,730, entitled “ZOOM LENS AND IMAGING APPARATUS,” filed Aug. 12, 2020, and which is hereby incorporated herein by reference in its entirety. 
    
    
     BACKGROUND 
     Technical Field 
     This disclosure relates generally to camera systems, and more specifically to magnification in small form factor cameras and lens systems. 
     Description of the Related Art 
     The advent of small, mobile multipurpose devices such as smartphones and tablet or pad devices has resulted in a need for high-resolution, small form factor cameras that are lightweight, compact, and capable of capturing high resolution, high quality images at low F-numbers for integration in the devices. However, due to limitations of conventional camera technology, conventional small cameras used in such devices tend to capture images at lower resolutions and/or with lower image quality than can be achieved with larger, higher quality cameras. Achieving higher resolution with small package size cameras generally requires use of a photosensor with small pixel size and a good, compact imaging lens system. Advances in technology have achieved reduction of the pixel size in photosensors. However, as photosensors become more compact and powerful, demand for compact imaging lens systems with improved imaging quality performance has increased. In addition, there are increasing expectations for small form factor cameras to be equipped with higher pixel count and/or larger pixel size image sensors (one or both of which may require larger image sensors), and features such as variable image magnification, while still maintaining a module height that is compact enough to fit into portable electronic devices. Thus, a challenge from an optical system design point of view is to provide an imaging lens system that is capable of capturing high brightness, high resolution images, with variable magnification capability under the physical constraints imposed by small form factor cameras. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    illustrates a camera that includes a folded lens system with a plurality of lens groups, some of which may be moved to various locations along an optic axis, according to various embodiments. 
         FIG.  2    illustrates a lens system including a light folding element and a plurality of lens groups, according to various embodiments. 
         FIGS.  3 A,  3 B,  3 C  illustrate a folded lens system that produces various magnifications, according to some embodiments. 
         FIG.  4    is a flowchart of a method of focusing an image or of changing magnification of an image of an object, the image produced by a lens system, according to some embodiments. 
         FIG.  5    is an illustration of a device that includes a camera employing a lens system as described herein, according to some embodiments 
         FIG.  6    illustrates an example computer system that includes a camera employing a lens system as described herein, according to some embodiments. 
     
    
    
     This specification includes references to “one embodiment” or “an embodiment.” The appearances of the phrases “in one embodiment” or “in an embodiment” do not necessarily refer to the same embodiment. Particular features, structures, or characteristics may be combined in any suitable manner consistent with this disclosure. 
     “Comprising.” This term is open-ended. As used in the appended claims, this term does not foreclose additional structure or steps. Consider a claim that recites: “An apparatus comprising one or more processor units . . . ”. Such a claim does not foreclose the apparatus from including additional components (e.g., a network interface unit, graphics circuitry, etc.). 
     “Configured To.” Various units, circuits, or other components may be described or claimed as “configured to” perform a task or tasks. In such contexts, “configured to” is used to connote structure by indicating that the units/circuits/components include structure (e.g., circuitry) that performs those task or tasks during operation. As such, the unit/circuit/component can be said to be configured to perform the task even when the specified unit/circuit/component is not currently operational (e.g., is not being electrically powered). The units/circuits/components used with the “configured to” language include hardware—for example, circuits, memory storing program instructions executable to implement the operation, etc. Reciting that a unit/circuit/component is “configured to” perform one or more tasks is expressly intended not to invoke 35 U.S.C. § 112(f), for that unit/circuit/component. Additionally, “configured to” can include generic structure (e.g., generic circuitry) that is manipulated by software and/or firmware (e.g., a field programmable gate array (FPGA) or a general-purpose processor executing software) to operate in manner that is capable of performing the task(s) at issue. “Configure to” may also include adapting a manufacturing process (e.g., a semiconductor fabrication facility) to fabricate devices (e.g., integrated circuits) that are adapted to implement or perform one or more tasks. 
     “First,” “Second,” etc. As used herein, these terms are used as labels for nouns that they precede, and do not imply any type of ordering (e.g., spatial, temporal, logical, etc.). For example, a buffer circuit may be described herein as performing write operations for “first” and “second” values. The terms “first” and “second” do not necessarily imply that the first value must be written before the second value. 
     “Based On.” As used herein, this term is used to describe one or more factors that affect a determination. This term does not foreclose additional factors that may affect a determination. That is, a determination may be solely based on those factors or based, at least in part, on those factors. Consider the phrase “determine A based on B.” While in this case, B is a factor that affects the determination of A, such a phrase does not foreclose the determination of A from also being based on C. In other instances, A may be determined based solely on B. 
     DETAILED DESCRIPTION 
     Embodiments of folded lens systems are described that may, for example, be used in small form factor cameras in mobile multipurpose devices such as smartphones and tablet or pad devices. A folded lens system may include one or more prisms and/or mirrors, and a lens stack of a plurality of lens groups, each lens group including one or more refractive lens elements such that positions of different ones of the lens groups along an optical axis may be varied, enabling magnification of an image to be varied, and enabling a “zoom” feature, e.g., continuous magnification of an image of an object between two endpoints of magnification. Magnification may be defined as a ratio of object height/image height. Focal length may be defined as a distance from a lens (e.g., center of a lens) to a focal point at which incoming parallel light is focused along an optic axis of the lens. 
     A telephoto lens (or telephoto lens system) is a lens that has narrow field of view. Embodiments may enable the zoom feature to permit variable focal length between approximately 78 millimeters (mm) and 130 mm in 35 mm equivalent focal length (EFL). In various embodiments, the lens system always operates as a telephoto lens. For example, in embodiments, the shortest 35 mm equivalent focal length of the lens system is 78 mm. The focal length may be varied continually in some embodiments, or may be varied in discrete steps. The initial 35 mm equivalent focal length and/or final 35 mm equivalent focal length in execution of the zoom may be determined based on user input. The 35 mm equivalent focal length may be defined by an equation as follows:
 
 f   35 mm   =f   eff ×43.266/ I   C  
 
where “f 35 mm ” is a 35 mm equivalent focal length, “f eff ” is an effective focal length of a lens system, and “I C ” is an image circle diameter of a lens system.
 
     In embodiments, the lens system comprises at least three movable lens groups, and may permit variable 35 mm equivalent focal length to be accomplished through movement along an optic axis of three (or more) of the lens groups in the folded lens system, the movement of the three (or more) lens groups occurring while other lens groups of the lens system remain fixed in their respective positions along the optical axis. The movable lens groups may be moved by actuators responsive to receipt of respective signals from a controller of a system. The controller may send the signals to the actuators responsive to a command received from, e.g., a user, such as a user of a portable device that includes the lens system as part of a camera. 
     Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. However, it will be apparent to one of ordinary skill in the art that some embodiments may be practiced without these specific details. In other instances, well-known methods, procedures, components, circuits, and networks have not been described in detail so as not to unnecessarily obscure aspects of the embodiments. 
       FIG.  1    illustrates a camera  100 , according to some embodiments. The camera includes a lens system  102 , an image sensor  116 , and a controller  118 . As shown in  FIG.  1   , the lens system  102  includes a plurality of lens groups  112  ( 112 X,  112 A,  112 Y,  112 B,  112 C, . . .  112 N). Light that is emitted from, or reflected from, an object  103  enters the system  100  as incident light  104 , which is reflected onto the optical axis  114 , is refracted by the plurality of lens groups  112 , and is received by the image sensor  116 , on which an image may be formed. In embodiments, there is no refractive element, e.g., lens, situated between the object  103  and a light folding element  106 . 
     Each of the lens groups  112  comprises one or more lenses that may be made from e.g., glass, a plastic material, or another material that is configured to receive light and refract the received light onto an optical axis such as optical axis  114 . Lens group  112 X includes a light-folding element  106  and a lens  108 . As shown in  FIG.  1   , the light-folding element is a prism-shaped element that is configured to reflect the incident light  104  received from the object  103 , onto an optical axis  114 . In an embodiment, the lens  108  has a positive refractive power. In some embodiments, a mirror may be employed as the light-folding element instead of the prism  106 . The lens group  112 X typically remains in a fixed position on the optical axis when a change in 35 mm equivalent focal length happens, e.g., responsive to a request from a user. In embodiments, there is not more than one lens (e.g., lens  108 ) situated between the light folding element and a first movable lens group  108 A. 
     In embodiments, at least three of the lens groups  112  are movable along an optical axis  114 . As indicated in  FIG.  1   , lens groups  112 A,  112 B, and  112 C are movable in either direction along the optical axis  114 . In other embodiments more than three of the lens groups  112  may be movable in either direction along the optical axis  114 . 
     The controller  118  comprises circuitry (e.g., processor(s), memory, input/output circuitry, etc.) configured to, in response to a request, send signals to each of a plurality of actuators  110 , each actuator configured to move a corresponding lens group to which the actuator is coupled, along the optical axis  114 . As shown in  FIG.  1   , each of the lens groups  112 A, B, C, is coupled to a respective actuator  110 A,  110 B,  110 C. In other embodiments, more than three lens groups may be coupled to respective actuators (not shown) and may be moved along the optical axis  114  by the respective coupled actuators, responsive to respective signals received from the controller  118 . 
     Some of the lens groups, e.g.,  112 X,  112 Y, may remain fixed in their positions on the optical axis during a change of 35 mm equivalent focal length of the camera  100 . Others of the lens groups, including movable lens groups, e.g.,  112 A,  112 B,  112 C, may change their respective positions along the optical axis  114  during a change of 35 mm equivalent focal length of the camera  100 , the movable lens groups being moved by respective actuators (e.g.,  110 A,  110 B,  110 C) in response to receipt of a corresponding signal from the controller. The signals may be generated by the controller in response to a request to change 35 mm equivalent focal length of the camera  100 , e.g., a request for “zoom-in” that increases 35 mm equivalent focal length from a starting 35 mm equivalent focal length to an ending 35 mm equivalent focal length. 
     In embodiments, a zoom-in request can result in a change from 35 mm equivalent focal length of 78 mm to up to 130 mm. In other embodiments, the starting 35 mm equivalent focal length may be greater than 78 mm. In some embodiments, the ending 35 mm equivalent focal length may be less than 130 mm. The amount of change of focal length may be indicated in the received request for zoom-in. In response to the received request to zoom-in, the controller  118  may send corresponding signals to actuators  110 A,  110 B,  110 C, and each of the actuators  110  may move the corresponding lens group  112  by a corresponding amount in a corresponding direction along the optical axis  114 . During a zoom-in operation, some of the movable lens groups may move along the optical axis  114  toward the image sensor  116 , while others of the movable lens groups may move in an opposite direction (away from the image sensor  116 ) along the optical axis  114 . 
     Conversely, a request may be received to “zoom-out” from a starting focal length to an ending focal length that is smaller than the starting focal length. For example, the lens system  102  may be configured to produce 130 mm in 35 mm equivalent focal length, and the zoom-out request may specify that the ending 35 mm equivalent focal length is to be 78 mm in 35 mm equivalent focal length. The controller  118 , upon receiving an indication of the request to zoom-out, may issue signals to the respective actuators  110  to move the corresponding movable lens groups, each to be moved in a direction opposite to the respective direction of movement that produces a “zoom-out” increase in 35 mm equivalent focal length. 
       FIG.  2    illustrates a lens system  200  that provides variable magnification of an image of an object that is within a field of view of the lens system  200 , according to some embodiments. The lens system  200 , as shown in  FIG.  2   , includes six lens groups: first lens group  202 , second lens group  204 , third lens group  206 , fourth lens group  208 , fifth lens group  210 , sixth lens group  212 . Also included in the depicted embodiment is aperture  214 , infrared filter  216  (optional), and image sensor  218 . Image sensor  218  is configured to receive light that has been projected by the lens system  200  at an image side of the lens system  200 . 
     In an embodiment, at least three of the lens groups may be moved (e.g., repositioned) along optical axis  224 . In an embodiment, the second lens group  204 , the fourth lens group  208 , and the fifth lens group  210  groups may be positioned along the optical axis  224 , including to be repositioned from a respective initial position so as to increase or decrease a magnitude of the image that is projected onto the image sensor  218 . In an embodiment, there is a total of six lens groups, and three of the six lens groups are fixed in position along the optical axis  224 , and three of the six lens groups are movable along the optical axis  224 , e.g., for the zoom function. 
     In an embodiment, first lens group  202  has a positive refractive power and includes a prism  230  and a lens  232  having positive refractive power. The prism  230  may receive light that is emitted or reflected from an object along the input axis  222 , and reflect the received light so as to redirect the received light along the optical axis  224 , which differs in orientation from the input axis  222 . In other embodiments, a reflective surface such as a mirror may be used instead of the prism to change the direction of the light received from the object, from the input axis  222  to the optical axis  224 . In embodiments, the lens system  200  has no lenses or refractive elements situated between the object side of the lens system  200  and the prism  230  (or reflective surface such as a mirror). That is, there are no refractive elements (e.g., lenses) between the prism  230  and the object from which light is emitted (or reflected) that enters the lens system  200  at the prism  230 . Stated in other words, there is no refractive element (e.g., lens) located at an object side of the reflective element (e.g., prism  230 ) either in contact with the object side of the reflective element or located toward the object side along the input axis  222 . 
     In an embodiment, the second lens group  204  has a negative refractive power and includes a lens with negative refractive power and a lens with a positive refractive power. In an embodiment, the second lens group  204  may be positioned as a group (e.g., the lenses of the second lens group  204  maintain fixed relative to one another) along the optical axis  224 . The position of the second lens group  204  may be varied along with movement of others of the lens groups to achieve different 35 mm equivalent focal lengths. In some embodiments, the second lens group  204  has no more than two lenses and when moved along the optical axis  224  the lenses move as a unit, e.g., remain together, moving as a single unit along the optical axis  224 . 
     In an embodiment, a third lens group  206  has a positive refractive power and includes a lens with a positive refractive power. In an embodiment, the third lens group  206  remains in a fixed position along the optical axis  224  during any 35 mm equivalent focal length change of the lens system  200 . Such a 35 mm equivalent focal length change is effected by a change in relative positions of other ones of the lens groups along the optical axis  224 . In some embodiments, the third lens group  206  has only a single lens (e.g., the third lens group  206  has only one lens). 
     In an embodiment, an aperture  214  is situated on the optical axis  224 , adjacent to the third lens group  206 , on a side of the third lens group  206  that is closer to the image sensor  218  than is another side of the third lens group  206 , the other side of the lens group  206  being closer to the second lens group  204 ). 
     In an embodiment, the fourth lens group  208  has a positive refractive power and includes at least one lens with a positive refractive power. In the embodiment illustrated in  FIG.  2   , the fourth lens group  208  includes two lenses  226  and  228 , at least one of which (e.g., lens  226 ) has positive refractive power. In an embodiment, the fourth lens group  208  has only two lenses (e.g., lenses  226  and  228 ). That is, in an embodiment, the fourth lens group  208  has two distinct lenses and the fourth lens group  208  has a positive refractive power. In an embodiment, the fourth lens group  208  may be positioned as a group (e.g., the lenses of the fourth lens group  208  maintain fixed positions relative to one another) along the optical axis  224 , and the position of the fourth lens group  208  may be varied along with repositioning others of the lens groups to achieve, at the image sensor  218 , different 35 mm equivalent focal lengths. 
     In an embodiment, the fifth lens group  210  has a negative refractive power and includes at least one lens having a negative refractive power. In an embodiment, the fifth lens group  210  has only one lens. In an embodiment a position of the fifth lens group  210  along the optical axis  224  may be varied along with repositioning of others of the lens groups to achieve, at the image sensor  218 , different magnifications of an object from which incoming light was received by the lens system  200  at the object side and different 35 mm equivalent focal lengths. 
     In embodiments, the sixth lens group  212  has a positive refractive power and includes at least one lens having a positive refractive power. In an embodiment, the sixth lens group  212  has only one lens. In an embodiment, the sixth lens group  206  is configured to remain in a fixed position along the optical axis  224  during any 35 mm equivalent focal length change. 
     In operation, the lens system  200  is configured to provide a selectable plurality of magnifications and 35 mm equivalent focal lengths, which may be effected through changing relative positions, along the optical axis  224 , of three or more of the lens groups  202 ,  204 ,  206 ,  208 ,  210 , and  212 . For example, in an embodiment, to effect from an initial magnification and an initial 35 mm equivalent focal length, an increase in the magnification of an image of an object whose associated light (emitted or reflected) is entrant to the lens system  200  along the input axis  222  and an increase in 35 mm equivalent focal length, the second lens group  204  may be displaced toward the image sensor  218 , the fourth lens group  208  may be displaced away from the image sensor  218 , and the fifth lens group  210  may be displaced away from the image sensor  218 . 
     In embodiments, the lens system  200  contains three movable lens groups and three fixed lens groups, and zoom is accomplished by moving the positions of each of the three movable lens groups along a common optical axis  224  while each of the three fixed lens groups remains stationary in their respective positions along the optical axis  224 . 
     In embodiments, an f number, (e.g., ratio of focal length of the system to a diameter of an entrance aperture) of the lens system  200 , (notated “f/(number)”), has a value between f/2.3 and f/3.0. In embodiments, in any telephoto magnification setting of the various lenses of the lens system  200 , the lens system  200  has an f number that is always less than or equal to 2.9, e.g., the f number is always &lt;f/3.0. In certain embodiments, with the lens system  200  configured to have 35 mm equivalent focal length of 78 mm the lens system  200  has a corresponding f number of f/2.3. In certain embodiments, with the lens system  200  configured to have 35 mm equivalent focal length of 130 mm, the lens system  200  has a corresponding f number of f/2.9. In embodiments, with the lens system  200  configured to have a 35 mm equivalent focal length of between 78 mm and 130 mm in 35 mm equivalent focal length, the lens system  200  has a corresponding f number of between f/2.3 and f/2.9. In some embodiments, the f number is always f&lt;3.0 for any 35 mm equivalent focal length configuration of the lens system. 
     In various embodiments, the lenses in the lens system  200  may include glass, or any of various optical grade plastics, or one or more other materials that are substantially transparent to light of wavelengths desired to be projected. 
     In embodiments, the lens system  200  has a total of not more than 8 lenses. In embodiments, the lens system  200  also includes only one light-folding element. In embodiments, the lens system  200  has only 8 refractive elements. In some embodiments, the lens system  200  has only 8 refractive elements (e.g., optical lenses) and only one light-folding element. 
     In various embodiments the fourth lens group  208  includes positive refractive power lens  226  that has an Abbe number (D) that has a value greater than 60. The Abbe number of a lens is related to chromatic aberration of the lens. Imposing the condition D&gt;60 may help to reduce chromatic aberration of the image directed to the image sensor  218 , in various embodiments. 
     For example, in an embodiment depicted in  FIG.  2   , the fourth lens group  208  includes a lenticular-shaped lens  226  that has a positive refractive power, and lens  228  that may have, e.g., a negative refractive power. In embodiments, the (positive lens)  226  has an associated Abbe number D&gt;60, which may improve image performance across an extent of varying 35 mm equivalent focal lengths by the lens system  200  throughout a range of 35 mm equivalent focal lengths of a zoom function of a camera that utilizes a lens system similar to lens system  200 . 
     In embodiments, the second lens group  204 , with focal length B, satisfies the following relationship to a focal length C of the lens system  200  at maximum focal length of the lens system  200 : −0.6&lt;B/C&lt;−0.1. This range of the focal length ratio B/C may be selected for several reasons: (1) the condition B/C&lt;−0.6 may be imposed to avoid an increase in thickness of the lens system (e.g., to compensate for an inadequate lens power of the 2 nd  lens group  204 ); (2) the condition B/C&lt;−0.1 may prevent an unacceptably large lens aberration due to a large lens power of the second lens group  204 , which lens aberration can cause degradation of the image that is output from the lens system  200 . 
     In embodiments, refractive index A of prismatic element  230  satisfies the following relationship: A&gt;1.7. Satisfaction of this condition may help to reduce an overall Z-dimension  250  (height) of the lens system. In embodiments, the Z-dimension  250  is less than or equal to 6.0 mm. 
     In embodiments, a lens system according to the arrangement depicted in  FIG.  2   , may allow a zoom function to vary 35 mm equivalent focal length of an image to between 78 mm and 130 mm of 35 mm equivalent focal length. 
     In embodiments similar to the embodiment depicted in  FIG.  2   , changes to the 35 mm equivalent focal length may be made by adjusting the respective positions of the second lens group, the fourth lens group, and the fifth lens group concurrently. In various embodiments, a change to the 35 mm equivalent focal length may be made using, e.g. stepper motors, piezoelectric actuators, voice coil motor (VCM) actuators, or another type of motion actuator. The focal length may be changed continuously (zoom) from a first 35 mm equivalent focal length to a second 35 mm equivalent focal length, e.g., from 78 mm to 130 mm or from 130 mm to 78 mm. Increasing 35 mm equivalent focal length may be referred to as “zoom-in” while decreasing 35 mm equivalent focal length may be referred to as “zoom-out.” 
     In embodiments, the equivalent focal length may be changed in increments according to a user-specified increment, e.g. increments of 13 mm starting from 78 mm to 91 mm, to 104 mm, to 117 mm to 130 mm, with the user determining when to increase the 35 mm equivalent focal length, or a user selection of incremental change in 35 mm equivalent focal length after a specified time period, e.g., increase by 13 mm every 15 seconds (or after another period of time that may be specified, e.g., by the user). Conversely, the 35 mm equivalent focal length may be varied (continuously or in discrete steps) from a second 35 mm equivalent focal length to a first 35 mm equivalent focal length, e.g., starting at 130 mm and reducing the 35 mm equivalent focal length to 78 mm. 
       FIGS.  3    A,B,C depicts the lens system of  FIG.  2    in various configurations. For each of  FIGS.  3 A,  3 B, and  3 C , various ones of the lens groups are positioned in respective positions along optical axis  324  to achieve a targeted 35 mm equivalent focal length (and associated magnification) of the lens system. That is, each of  FIGS.  3 A,  3 B, and  3 C  reflects a respective configuration of the lens groups for a corresponding 35 mm equivalent focal length.  FIGS.  3 A,  3 B, and  3 C  indicate relative positions of the six lens groups, and are not intended to represent actual distances between lens groups; that is,  FIGS.  3 A , B, C are not drawn to scale with respect to an intended 35 mm equivalent focal length of an object. 
     Turning to  FIG.  3 A , the components of lens system  300  are located along optical axis  324  in order from left to right: first lens group  302 , second lens group  304 , third lens group  306 , fourth lens group  308 , fifth lens group  310 , sixth lens group  312 . Also shown in  FIG.  3 A  are (optional) infrared filter  316  and image sensor  318 . The lens system  300  projects an image, on the image sensor  318 , of an object (not shown) that emits and/or reflects incident light  301  received by a light-folding element (e.g., prism) of the first lens group  302 . The incident light  301  is folded by the light-folding element onto the optical axis  324  and is projected as an image onto image sensor  318 . The lens system  300  may be configured to provide a range of 35 mm equivalent focal lengths. For example, the lens system  300  may be configurable to provide a 35 mm equivalent focal length range between approximately 78 mm and approximately 130 mm corresponding to a change of an image size of the object from which light  301  is received. For example, to change 35 mm equivalent focal length and corresponding magnification of an image formed by the lens system  300  onto the image sensor  318 , lens groups  304 ,  308 , and  310  may be moved along the optical axis  324 , each moving by a respective amount and each moved in a respective direction along the optical axis. Additionally, the image may be focused on the image sensor  318  by varying (e.g., “fine tuning” along the optical axis  324 ) the position of lens group  310  along the optical axis  324 . In some embodiments, after changing 35 mm equivalent focal length and corresponding magnification of the image, focusing of the image is accomplished by varying the position of lens group  310  along the optical axis  324  while all other lens groups are kept in their respective positions along the optical axis  324 . Lens groups  302 ,  306 , and  312  remain fixed in their respective positions along the optical axis  324  during a change of 35 mm equivalent focal length of the lens system  300 . 
       FIG.  3 A  illustrates relative positions of the plurality of lens groups at an initial magnification.  FIG.  3 B  depicts the lens system  300  reconfigured from  FIG.  3 A  in order to provide greater 35 mm equivalent focal length (and corresponding greater magnification) than the configuration of  FIG.  3 A . Three of the lens groups in  FIG.  3 B  ( 304 ,  308 ,  310 ) are shifted in position from their positions in  FIG.  3 A , which results in a greater 35 mm equivalent focal length, and a corresponding higher magnification of the image produced at the image sensor. The first lens group  302  remains in the same position as in  FIG.  3 A . The second lens group  304  is translated toward the image sensor  318 , e.g., away from the first lens group  302  and toward the lens group  306 . The third lens group  306  remains stationary with respect to the image sensor  318  and with respect to the first lens group  302 ; that is, in  FIG.  3 B  the third lens group  306  is not moved from its position in  FIG.  3 A . The fourth lens group  308  is moved away from the image sensor  318 , toward the third lens group  306  and toward the first lens group  302 . The fifth lens group  310  is translated away from the image sensor  318 , toward the third lens group  306 . The sixth lens group  312  remains fixed in position as compared with its position in  FIG.  3 A , and stationary with respect to the third lens group  306 . After changing the position of lens groups  304 ,  308 , and  310 , additional focusing of the image directed to the image sensor  318  may be achieved by making slight adjustments (“fine tuning”) of the position of the fifth lens group  310  along the optical axis  324 , while each of the lens groups  304 ,  308  remain in their relocated positions shown in  FIG.  3 B . 
     Thus, an increase in 35 mm equivalent focal length (and corresponding magnification) may be achieved by moving (with respect to their corresponding positions as shown in  FIG.  3 A ) the second lens group  304  along the optical axis  324  in a direction toward the image sensor  318  and away from the first lens group  302 ; moving the fourth lens group  308  along the optical axis  324  in a direction away from the image sensor  318 ; and moving the fifth lens group  310  along the optical axis  324  in a direction away from the image sensor  318 , while the first lens group  302 , the third lens group  306 , and the sixth lens group  312  remain fixed in their corresponding positions. After moving the lens group  310  along the optical axis  324  in the direction away from the image sensor  318 , focusing (e.g., fine tuning, sharpening) of the focus of the image at the image sensor  318  may be achieved by making small changes in position of the fifth lens group  310  along the optical axis  324 , while each of the other lens groups that have been moved, e.g.,  304 ,  308  remain in their relocated positions, which are relocated from their respective positions shown in  FIG.  3 A . In embodiments, in order to focus the image projected onto the image sensor  318  after the change magnification has been achieved, only the fifth lens group  310  is varied in its position along the optical axis  324 , while each of the other lens groups  302 ,  304 ,  306 ,  308 ,  312  is maintained in its position along the optical axis  324 . That is, after the desired 35 mm equivalent focal length and corresponding magnification change is achieved, only lens group  310  is varied in its location along the optical axis  324 , while the other movable lens groups  304  and  308  are not moved during focusing of the image projected onto the image sensor  318 . 
       FIG.  3 C  shows relative positions of each of the lens groups  302 - 312 , some of which have been relocated with respect to their positions shown in  FIG.  3 B . To further increase the 35 mm equivalent focal length (and corresponding magnification) from the 35 mm equivalent focal length and magnification achieved in  FIG.  3 B , the second lens group  304  is translated further toward the image sensor  318  (and further toward the third lens group  306  that is fixed in position), the fourth lens group  310  is translated further away from the image sensor  318  (and further toward the third lens group  306  that is fixed in position), and the fifth lens group  310  is translated further away from the image sensor  318 . The first lens group  302 , the third lens group  306 , and the sixth lens group  312  each remain fixed in position with respect to their corresponding positions shown in  FIGS.  3 A and  3 B . Focusing (e.g., increasing image sharpness) of the image at the image sensor  318  may be achieved (e.g., after having moved the lens group  310  in a direction away from the image sensor  318 ) by making additional small changes to the position of lens group  310  along the optical axis  324 . 
     In an embodiment, the lens system  300  can be operated as a telephoto lens system (a “zoom” lens system) that can change 35 mm equivalent focal length between, e.g., 78 mm and 130 mm in 35 mm equivalent focal length by adjusting the relative positions of the second lens group  304 , the fourth lens group  308 , and the fifth lens group  310 , as described above. The 35 mm equivalent focal length may be increased by translation along the optical axis  324 , of each of three of the lens groups: moving the second lens group  304  away from the first lens group  302  and toward the image sensor  318 ; moving the fourth lens group  308  in the direction away from the image sensor  318  and toward the first lens group  302 ; and moving the fifth lens group away from the image sensor  318  and toward the first lens group  302 . Each of the first lens group  302 , the third lens group  306 , and the sixth lens group  312  is maintained at a fixed position in each of the 35 mm equivalent focal length configurations. 
     By moving each of the second lens group  304 , the fourth lens group  308 , and the fifth lens group  310  in a continuous fashion, a zoom-in effect, e.g., a continual change in 35 mm equivalent focal length from a smallest 35 mm equivalent focal length achievable by the lens system  300  to a largest 35 mm equivalent focal length achievable by the lens system  300 , as illustrated by the progressive changes in position of lens groups  304 ,  308 , and  310  from  FIG.  3 A , to  FIG.  3 B , to  FIG.  3 C . 
     A zoom-out effect (reduction of 35 mm equivalent focal length), may be achieved by moving the lens groups  304 ,  308 , and  310  oppositely to their respective motions for zoom-in. 
     Alternatively, a range of 35 mm equivalent focal lengths may be selected, e.g., by a user, and the lens system  300  may be configured to automatically zoom within the user-selected 35 mm equivalent focal length range. In an embodiment, the user may select to “zoom in” (increase 35 mm equivalent focal length), or to “zoom out” (decrease 35 mm equivalent focal length). In some embodiments, the user may set one or more of the minimum 35 mm equivalent focal length, maximum 35 mm equivalent focal length, and rate of change of 35 mm equivalent focal length. 
     In an embodiment, the user may select a particular 35 mm equivalent focal length for the lens system  300 , and upon a user request the lens system  300  may be automatically configured to provide the particular 35 mm equivalent focal length selected based on user input. Reconfiguration of the lens system  300  may be accomplished via one or more actuators, e.g., stepper motors, piezoelectric controllers, VCM motors, etc. controlled by one or more controllers that include one or more respective processors, the particular 35 mm equivalent focal length based on input from, e.g. the user. 
     In another embodiment, the lens system  300  may be configurable to have the 35 mm equivalent focal length adjusted manually based on user input, e.g., a manually entered change (e.g., knob change) may result in a reconfiguration of the lens system  300  to either increase 35 mm equivalent focal length or decrease 35 mm equivalent focal length by moving each of the lens groups  304 ,  308 , and  310  through mechanical means such as through a combination of gears, levers, etc. 
       FIG.  4    is a flow diagram of a method of increasing magnification of an image produced by a lens system, such as the lens systems of  FIGS.  1 - 3   . 
     At decision diamond  402 , a selection is made as to whether a change in magnification produced by the lens system is desired, or a focus of an image at the current magnification. 
     If it is desired to focus the image produced by the lens system at the current magnification, moving to block  404  a controller sends one or more control signals to a single actuator C that is coupled to a single lens group (the lens group  210  of  FIG.  2   , also the lens group  310  of  FIG.  3   ), which causes, at block  406  the actuator C to move the lens group to which the actuator is coupled, in small increments along the optical axis until focus is achieved (e.g., through an auto-focus feedback system, or via user feedback). The method then returns to the decision diamond  402 . 
     If, at the decision diamond  402 , a change in magnification produced by the lens system is desired, moving to decision diamond  406  it is determined whether the change in magnification is to be an increase (zoom-in) or a decrease (zoom-out) in magnification. 
     If an increase in magnification (zoom-in) is desired, taking the left branch of the flow chart  400 , at blocks  410 A,  410 B,  410 C control signals A, B, and C, are generated (e.g., by a controller), each of which is to operate a corresponding actuator A, B, and C. Blocks  410 A,  410 B, and  410 C may be executed in any order, or in parallel. Responsive to the corresponding control signal received, at block  414 A actuator A moves a corresponding lens group A by a first amount in a direction toward the image side. At block  414 B actuator B move lens group B by a second amount in an opposite direction toward an object side (e.g., away from the image side). At block  414 C actuator C moves lens group C by a third amount in the direction toward the object side (away from the image side). The distances moved by each of the lens groups A, B, C, will generally not be the same. Instead, the distances moved are determined (e.g., by control circuitry such as a controller that generates signals to the actuators) based on the change in magnification to be achieved. The method ends at  418 . 
     If a decrease in magnification (zoom-out) is desired, taking the right branch of the flow chart  400 , at blocks  412 A,  412 B,  412 C, respective control signals A, B, and C, are generated (e.g., by a controller), each of which is to operate a corresponding actuator A, B, and C. Blocks  412 A,  412 B, and  412 C may be executed in any order. Responsive to the corresponding control signal received, at block  416 A actuator A moves a corresponding lens group A by a first amount on the optical axis in a direction toward the object side and away from the image side. At block  416 B actuator B moves lens group B by a second amount on the optical axis in an opposite direction, which is toward the image side (e.g., away from the object side). At block  416 C actuator C moves lens group C by a third amount on the optical axis in the direction toward the image side (away from the object side). Generally the distances moved by each of the lens groups A, B, C, will not be the same. Instead, the distances moved are determined (e.g. by control circuitry) based on the change in magnification to be achieved. The method ends at  420 . 
       FIG.  5    illustrates a schematic representation of an example device  500  that may include a camera (e.g., camera  100  in  FIG.  1   ) that includes moveable lens groups (e.g., as described above with reference to  FIGS.  1 - 4   ), according to some embodiments, in accordance with some embodiments. In some embodiments, the device  500  may be a mobile device and/or a multifunction device. In various embodiments, the device  500  may be any of various types of devices, including, but not limited to, a personal computer system, desktop computer, laptop, notebook, tablet, slate, pad, or netbook computer, mainframe computer system, handheld computer, workstation, network computer, a camera, a set top box, a mobile device, an augmented reality (AR) and/or virtual reality (VR) headset, a consumer device, video game console, handheld video game device, application server, storage device, a television, a video recording device, a peripheral device such as a switch, modem, router, or in general any type of computing or electronic device. 
     In some embodiments, the device  500  may include a display system  502  (e.g., comprising a display and/or a touch-sensitive surface) and/or one or more cameras  504 . In some non-limiting embodiments, the display system  502  and/or one or more front-facing cameras  504   a  may be provided at a front side of the device  500 , e.g., as indicated in  FIG.  5   . Additionally, or alternatively, one or more rear-facing cameras  504   b  may be provided at a rear side of the device  500 . In some embodiments comprising multiple cameras  504 , some or all of the cameras may be the same as, or similar to, each other. Additionally, or alternatively, some or all of the cameras may be different from each other. In various embodiments, the location(s) and/or arrangement(s) of the camera(s)  504  may be different than those indicated in  FIG.  5   . 
     Among other things, the device  500  may include memory  506  (e.g., comprising an operating system  508  and/or application(s)/program instructions  510 ), one or more processors and/or controllers  512  (e.g., comprising CPU(s), memory controller(s), display controller(s), and/or camera controller(s), etc.), and/or one or more sensors  516  (e.g., orientation sensor(s), proximity sensor(s), and/or position sensor(s), etc.). In some embodiments, the device  500  may communicate with one or more other devices and/or services, such as computing device(s)  518 , cloud service(s)  520 , etc., via one or more networks  522 . For example, the device  500  may include a network interface (e.g., network interface  610 ) that enables the device  500  to transmit data to, and receive data from, the network(s)  522 . Additionally, or alternatively, the device  500  may be capable of communicating with other devices via wireless communication using any of a variety of communications standards, protocols, and/or technologies. 
       FIG.  6    illustrates a schematic block diagram of an example computing device, referred to as computer system  600 , that may include or host embodiments of a camera that includes moveable lens groups (e.g., as described above with reference to  FIGS.  1 - 4   ), according to some embodiments, e.g., as described herein with reference to  FIGS.  1 - 5   . In addition, computer system  600  may implement methods for controlling operations of the camera and/or for performing image processing images captured with the camera. In some embodiments, the device  500  (described herein with reference to  FIG.  5   ) may additionally, or alternatively, include some or all of the functional components of the computer system  600  described herein. 
     The computer system  600  may be configured to execute any or all of the embodiments described above. In different embodiments, computer system  600  may be any of various types of devices, including, but not limited to, a personal computer system, desktop computer, laptop, notebook, tablet, slate, pad, or netbook computer, mainframe computer system, handheld computer, workstation, network computer, a camera, a set top box, a mobile device, an augmented reality (AR) and/or virtual reality (VR) headset, a consumer device, video game console, handheld video game device, application server, storage device, a television, a video recording device, a peripheral device such as a switch, modem, router, or in general any type of computing or electronic device. 
     In the illustrated embodiment, computer system  600  includes one or more processors  602  coupled to a system memory  604  via an input/output (I/O) interface  606 . Computer system  600  further includes one or more cameras  608  coupled to the I/O interface  606 . Computer system  600  further includes a network interface  610  coupled to I/O interface  606 , and one or more input/output devices  612 , such as cursor control device  614 , keyboard  616 , and display(s)  618 . In some cases, it is contemplated that embodiments may be implemented using a single instance of computer system  600 , while in other embodiments multiple such systems, or multiple nodes making up computer system  600 , may be configured to host different portions or instances of embodiments. For example, in one embodiment some elements may be implemented via one or more nodes of computer system  600  that are distinct from those nodes implementing other elements. 
     In various embodiments, computer system  600  may be a uniprocessor system including one processor  602 , or a multiprocessor system including several processors  602  (e.g., two, four, eight, or another suitable number). Processors  602  may be any suitable processor capable of executing instructions. For example, in various embodiments processors  602  may be general-purpose or embedded processors implementing any of a variety of instruction set architectures (ISAs), such as the x86, PowerPC, SPARC, or MIPS ISAs, or any other suitable ISA. In multiprocessor systems, each of processors  602  may commonly, but not necessarily, implement the same ISA. 
     System memory  604  may be configured to store program instructions  620  accessible by processor  602 . In various embodiments, system memory  604  may be implemented using any suitable memory technology, such as static random access memory (SRAM), synchronous dynamic RAM (SDRAM), nonvolatile/Flash-type memory, or any other type of memory. Additionally, existing camera control data  622  of memory  604  may include any of the information or data structures described above. In some embodiments, program instructions  620  and/or data  622  may be received, sent or stored upon different types of computer-accessible media or on similar media separate from system memory  604  or computer system  600 . In various embodiments, some or all of the functionality described herein may be implemented via such a computer system  600 . 
     In one embodiment, I/O interface  606  may be configured to coordinate I/O traffic between processor  602 , system memory  604 , and any peripheral devices in the device, including network interface  610  or other peripheral interfaces, such as input/output devices  612 . In some embodiments, I/O interface  606  may perform any necessary protocol, timing or other data transformations to convert data signals from one component (e.g., system memory  604 ) into a format suitable for use by another component (e.g., processor  602 ). In some embodiments, I/O interface  606  may include support for devices attached through various types of peripheral buses, such as a variant of the Peripheral Component Interconnect (PCI) bus standard or the Universal Serial Bus (USB) standard, for example. In some embodiments, the function of I/O interface  606  may be split into two or more separate components, such as a north bridge and a south bridge, for example. Also, in some embodiments some or all of the functionality of I/O interface  606 , such as an interface to system memory  604 , may be incorporated directly into processor  602 . 
     Network interface  610  may be configured to allow data to be exchanged between computer system  600  and other devices attached to a network  624  (e.g., carrier or agent devices) or between nodes of computer system  600 . Network  624  may in various embodiments include one or more networks including but not limited to Local Area Networks (LANs) (e.g., an Ethernet or corporate network), Wide Area Networks (WANs) (e.g., the Internet), wireless data networks, some other electronic data network, or some combination thereof. In various embodiments, network interface  610  may support communication via wired or wireless general data networks, such as any suitable type of Ethernet network, for example; via telecommunications/telephony networks such as analog voice networks or digital fiber communications networks; via storage area networks such as Fibre Channel SANs, or via any other suitable type of network and/or protocol. 
     Input/output devices  612  may, in some embodiments, include one or more display terminals, keyboards, keypads, touchpads, scanning devices, voice or optical recognition devices, or any other devices suitable for entering or accessing data by one or more computer systems  600 . Multiple input/output devices  612  may be present in computer system  600  or may be distributed on various nodes of computer system  600 . In some embodiments, similar input/output devices may be separate from computer system  600  and may interact with one or more nodes of computer system  600  through a wired or wireless connection, such as over network interface  610 . 
     Those skilled in the art will appreciate that computer system  600  is merely illustrative and is not intended to limit the scope of embodiments. In particular, the computer system and devices may include any combination of hardware or software that can perform the indicated functions, including computers, network devices, Internet appliances, PDAs, wireless phones, pagers, etc. Computer system  600  may also be connected to other devices that are not illustrated, or instead may operate as a stand-alone system. In addition, the functionality provided by the illustrated components may in some embodiments be combined in fewer components or distributed in additional components. Similarly, in some embodiments, the functionality of some of the illustrated components may not be provided and/or other additional functionality may be available. 
     Those skilled in the art will also appreciate that, while various items are illustrated as being stored in memory or on storage while being used, these items or portions of them may be transferred between memory and other storage devices for purposes of memory management and data integrity. Alternatively, in other embodiments some or all of the software components may execute in memory on another device and communicate with the illustrated computer system via inter-computer communication. Some or all of the system components or data structures may also be stored (e.g., as instructions or structured data) on a computer-accessible medium or a portable article to be read by an appropriate drive, various examples of which are described above. In some embodiments, instructions stored on a computer-accessible medium separate from computer system  600  may be transmitted to computer system  600  via transmission media or signals such as electrical, electromagnetic, or digital signals, conveyed via a communication medium such as a network and/or a wireless link. Various embodiments may further include receiving, sending or storing instructions and/or data implemented in accordance with the foregoing description upon a computer-accessible medium. Generally speaking, a computer-accessible medium may include a non-transitory, computer-readable storage medium or memory medium such as magnetic or optical media, e.g., disk or DVD/CD-ROM, volatile or non-volatile media such as RAM (e.g. SDRAM, DDR, RDRAM, SRAM, etc.), ROM, etc. In some embodiments, a computer-accessible medium may include transmission media or signals such as electrical, electromagnetic, or digital signals, conveyed via a communication medium such as network and/or a wireless link. 
     The methods described herein may be implemented in software, hardware, or a combination thereof, in different embodiments. In addition, the order of the blocks of the methods may be changed, and various elements may be added, reordered, combined, omitted, modified, etc. Various modifications and changes may be made as would be obvious to a person skilled in the art having the benefit of this disclosure. The various embodiments described herein are meant to be illustrative and not limiting. Many variations, modifications, additions, and improvements are possible. Accordingly, plural instances may be provided for components described herein as a single instance. Boundaries between various components, operations and data stores are somewhat arbitrary, and particular operations are illustrated in the context of specific illustrative configurations. Other allocations of functionality are envisioned and may fall within the scope of claims that follow. Finally, structures and functionality presented as discrete components in the example configurations may be implemented as a combined structure or component. These and other variations, modifications, additions, and improvements may fall within the scope of embodiments as defined in the claims that follow.

Metadata:
Filing Date: 20210811
Publication Date: 20240604
Grant Date: 20240604
Priority Date: 20200812
Inventors: HOSOI, MASAHARU
SHINOHARA, YOSHIKAZU
Assignee: APPLE INC
CPC Classifications: [{"code": "G02B13/009", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02B15/1461", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B15/20", "inventive": true, "first": false, "tree": "[]"}, {"code": "G03B13/34", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02B13/0065", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02B13/009", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02B7/102", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B15/146", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B15/1461", "inventive": true, "first": false, "tree": "[]"}, {"code": "G03B30/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B9/62", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B15/1461", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B15/20", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B15/1461", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 80224185