PATENT DOCUMENT

Publication Number: US-10440301-B2
Application Number: US-201715699806-A
Country: US
Kind Code: B2

Title: Image capture device, pixel, and method providing improved phase detection auto-focus performance

Abstract:
An image capture device, pixel, and method of determining a focus setting for an image capture device are described. The image capture device includes an imaging area and a pixel readout circuit. The imaging area includes a plurality of pixels. The plurality of pixels includes multiple pixels in which each pixel of the multiple pixels includes a two-dimensional array of photodetectors and a microlens. Each photodetector in the array of photodetectors for a pixel is electrically isolated from each other photodetector in the array of photodetectors. A microlens is disposed over the array of photodetectors for the pixel. The pixel readout circuit includes, per pixel, a shared readout circuit associated with the array of photodetectors for the pixel and a set of charge transfer transistors. Each charge transfer transistor is operable to connect a photodetector in the array of photodetectors to the shared readout circuit.

Claims:
What is claimed is: 
     
       1. An image capture device, comprising:
 an imaging area comprising a plurality of color-filtered pixels arranged in Bayer pattern rows and Bayer pattern columns, wherein:
 each color-filtered pixel comprises a two-dimensional array of photodetectors; 
 each photodetector in an array of photodetectors is electrically isolated from each other photodetector in the array of photodetectors; and 
 a different microlens is disposed over each array of photodetectors; 
 
 a pixel readout circuit comprising, for each color-filtered pixel:
 a shared readout circuit associated with the array of photodetectors for the color-filtered pixel; and 
 a set of charge transfer transistors, each charge transfer transistor operable to connect a photodetector in the array of photodetectors to the shared readout circuit; and 
 
 a processor configured to:
 operate the sets of charge transfer transistors for the color-filtered pixels in a first Bayer pattern row to detect a first phase difference in a first set of edges of an image; and 
 operate the sets of charge transfer transistors for the color-filtered pixels in a second Bayer pattern row to detect a second phase difference in a second set of edges of the image, the first set of edges orthogonal to the second set of edges. 
 
 
     
     
       2. The image capture device of  claim 1  wherein each shared readout circuit comprises a floating diffusion node. 
     
     
       3. The image capture device of  claim 2 , wherein the processor is configured to operate a first set of charge transfer transistors for a first color-filtered pixel to simultaneously transfer charge from a pair of photodetectors of the first color-filtered pixel to a first floating diffusion node of the first color-filtered pixel, the pair of photodetectors selected from:
 a first pair of photodetectors in a first row; 
 a second pair of photodetectors in a second row; 
 a third pair of photodetectors in a first column; and 
 a fourth pair of photodetectors in a second column. 
 
     
     
       4. The image capture device of  claim 1 , further comprising:
 a lens, wherein the processor is configured to:
 identify an out-of-focus condition from at least one of the first phase difference or the second phase difference; and 
 adjust a relationship between the plurality of color-filtered pixels and the lens. 
 
 
     
     
       5. The image capture device of  claim 1 , wherein each color-filtered pixel comprises a color filter disposed between the microlens and the array of photodetectors for the color-filtered pixel. 
     
     
       6. The image capture device of  claim 1 , wherein a peripheral portion of each microlens has a convex shape. 
     
     
       7. The image capture device of  claim 1 , wherein:
 operating the sets of charge transfer transistors for the color-filtered pixels in the first Bayer pattern row to detect the first phase difference comprises configuring a first set of charge transfer transistors for a first pixel to sum charges of a first pair of photodetectors aligned along a first direction; 
 operating the sets of charge transfer transistors for the color-filtered pixels in the second Bayer pattern row to detect the second phase difference comprises configuring a second set of charge transfer transistors for a second pixel to sum charges of a second pair of photodetectors aligned along a second direction. 
 
     
     
       8. An image capture device, comprising:
 an imaging area comprising a plurality of color-filtered pixels arranged in Bayer pattern rows and Bayer pattern columns, wherein:
 each color-filtered pixel comprises a two-dimensional array of photodetectors; 
 each photodetector in an array of photodetectors is electrically isolated from each other photodetector in the array of photodetectors; and 
 a different microlens is disposed over each array of photodetectors; 
 
 a pixel readout circuit comprising, for each color-filtered pixel:
 a shared readout circuit associated with the array of photodetectors for the color-filtered pixel; and 
 a set of charge transfer transistors, each charge transfer transistor operable to connect a photodetector in the array of photodetectors to the shared readout circuit; and 
 
 a processor configured to:
 operate the sets of charge transfer transistors for the color-filtered pixels in a first Bayer pattern column to detect a first phase difference in a first set of edges of an image; and 
 operate the sets of charge transfer transistors for the color-filtered pixels in a second Bayer pattern column to detect a second phase difference in a second set of edges of the image, the first set of edges orthogonal to the second set of edges. 
 
 
     
     
       9. The image capture device of  claim 8  wherein each shared readout circuit comprises a floating diffusion node. 
     
     
       10. The image capture device of  claim 9 , wherein the processor is configured to operate a first set of charge transfer transistors for a first color-filtered pixel to simultaneously transfer charge from a pair of photodetectors of the first color-filtered pixel to a first floating diffusion node of the first color-filtered pixel, the pair of photodetectors selected from:
 a first pair of photodetectors in a first row; 
 a second pair of photodetectors in a second row; 
 a third pair of photodetectors in a first column; and 
 a fourth pair of photodetectors in a second column. 
 
     
     
       11. The image capture device of  claim 8 , further comprising:
 a lens, wherein the processor is configured to:
 identify an out-of-focus condition from at least one of the first phase difference or the second phase difference; and 
 adjust a relationship between the plurality of color-filtered pixels and the lens. 
 
 
     
     
       12. The image capture device of  claim 8 , wherein each color-filtered pixel comprises a color filter disposed between the microlens and the array of photodetectors for the color-filtered pixel. 
     
     
       13. The image capture device of  claim 8 , wherein a peripheral portion of each microlens has a convex shape. 
     
     
       14. The image capture device of  claim 8 , wherein:
 operating the sets of charge transfer transistors for the color-filtered pixels in the first Bayer pattern column to detect the first phase difference comprises configuring a first set of charge transfer transistors for a first pixel to sum charges of a first pair of photodetectors aligned along a first direction; 
 operating the sets of charge transfer transistors for the color-filtered pixels in the second Bayer pattern column to detect the second phase difference comprises configuring a second set of charge transfer transistors for a second pixel to sum charges of a second pair of photodetectors aligned along a second direction. 
 
     
     
       15. An image capture device, comprising:
 an imaging area comprising a plurality of color-filtered pixels arranged in Bayer pattern rows and Bayer pattern columns, wherein:
 each color-filtered pixel comprises a two-dimensional array of photodetectors; 
 each photodetector in an array of photodetectors is electrically isolated from each other photodetector in the array of photodetectors; and 
 a different microlens is disposed over each array of photodetectors; 
 
 a pixel readout circuit comprising, for each color-filtered pixel:
 a shared readout circuit associated with the array of photodetectors for the color-filtered pixel; and 
 a set of charge transfer transistors, each charge transfer transistor operable to connect a photodetector in the array of photodetectors to the shared readout circuit; and 
 
 a processor configured to:
 operate the sets of charge transfer transistors for a first set of color-filtered pixels in a first Bayer pattern column to detect a first phase difference in a first set of edges of an image; 
 operate the sets of charge transfer transistors for a second set of color-filtered pixels in the first Bayer pattern column to detect a second phase difference in a second set of edges of the image, the first set of edges orthogonal to the second set of edges; 
 operate the sets of charge transfer transistors for a third set of color-filtered pixels in a second Bayer pattern column to detect the first phase difference in the first set of edges of the image; and 
 operate the sets of charge transfer transistors for a fourth set of color-filtered pixels in the second Bayer pattern column to detect the second phase difference in the second set of edges of the image. 
 
 
     
     
       16. The image capture device of  claim 15  wherein each shared readout circuit comprises a floating diffusion node. 
     
     
       17. The image capture device of  claim 16 , wherein the processor is configured to operate a first set of charge transfer transistors for a first color-filtered pixel to simultaneously transfer charge from a pair of photodetectors of the first color-filtered pixel to a first floating diffusion node of the first color-filtered pixel, the pair of photodetectors selected from:
 a first pair of photodetectors in a first row; 
 a second pair of photodetectors in a second row; 
 a third pair of photodetectors in a first column; and 
 a fourth pair of photodetectors in a second column. 
 
     
     
       18. The image capture device of  claim 15 , further comprising:
 a lens, wherein the processor is configured to:
 identify an out-of-focus condition from at least one of the first phase difference or the second phase difference; and 
 adjust a relationship between the plurality of color-filtered pixels and the lens. 
 
 
     
     
       19. The image capture device of  claim 15 , wherein each color-filtered pixel comprises a color filter disposed between the microlens and the array of photodetectors for the color-filtered pixel. 
     
     
       20. The image capture device of  claim 15 , wherein a peripheral portion of each microlens has a convex shape.

Description:
FIELD 
     The described embodiments relate generally to a device having a camera or other image capture device. More particularly, the described embodiments relate to an image capture device, pixel, and method of operating an image capture device or pixel, that provides improved phase detection auto-focus (PDAF) performance for a device having a camera or other image capture device. 
     BACKGROUND 
     Cameras and other image capture devices often use an image sensor, such as a charge-coupled device (CCD) image sensor or a complementary metal-oxide-semiconductor (CMOS) image sensor, to capture an image. In some cases, a camera or other image capture device may use multiple image sensors, with the different image sensors having adjacent or interlaced arrays of pixels. 
     Many cameras and other image capture devices include one or more optical components (e.g., a lens) that are configurable to focus light received or reflected from an image on the surface of an image sensor. Before or while capturing an image, the distance between the optical component(s) and image sensor (or a tilt or other parameters of the optical components or image sensor) may be adjusted to focus an image on the image sensor. In some cases, macro (or rough) focusing may be performed for an image sensor prior to capturing an image using the image sensor (e.g., using a macro focus mechanism adjacent the image sensor). Micro (or fine) focusing is often performed after acquiring one or more images using the image sensor. Many cameras and other image capture devices perform focusing operations frequently, and in some cases before or after each image capture frame. 
     Focusing an image on an image sensor often entails identifying a perceptible edge between objects, or an edge defined by different colors or brightness (e.g., an edge between dark and light regions), and bringing the edge into focus. Because low light conditions tend to mute the edges in an image, focusing an image on an image sensor can be particularly difficult under low light conditions, and an optimum focus may take longer to achieve or not be possible. 
     SUMMARY 
     Embodiments of the systems, devices, methods, and apparatus described in the present disclosure are directed to an image capture device, pixel, or method of operating an image capture device or pixel, that provides improved PDAF performance for a device having a camera or other image capture device. 
     In a first aspect, the present disclosure describes an image capture device. The image capture device may include an imaging area and a pixel readout circuit. The imaging area may include a plurality of pixels. Multiple pixels of the plurality of pixels may each include a two-dimensional array of photodetectors and a microlens. Each photodetector in the array of photodetectors for a pixel may be electrically isolated from each other photodetector in the array of photodetectors. A microlens may be disposed over the array of photodetectors for the pixel. The pixel readout circuit may include, per pixel, a shared readout circuit associated with the array of photodetectors for the pixel and a set of charge transfer transistors. Each charge transfer transistor may be operable to connect a photodetector in the array of photodetectors to the shared readout circuit. 
     In another aspect, the present disclosure describes a pixel. The pixel may include an imaging area, a microlens, and a same color light filter. The imaging area may include a two-dimensional array of photodetectors, with each photodetector in the array of photodetectors being electrically isolated from each other photodetector in the array of photodetectors. The microlens may be disposed over the array of photodetectors. The microlens may include a light-receiving side opposite the array of photodetectors. The light-receiving side of the microlens may include a central portion and peripheral portion. The peripheral portion of the microlens may be configured to redirect at least a portion of light incident on the peripheral portion toward a corresponding peripheral portion of the imaging area. The same color light filter may be disposed over the array of photodetectors. 
     In still another aspect of the disclosure, a method of determining a focus setting for an image capture device is described. The image capture device may include an image sensor having a plurality of pixels. The plurality of pixels may include multiple pixels that each include a two-dimensional array of photodetectors disposed under a microlens. Each photodetector in the array of photodetectors may be electrically isolated from each other photodetector in the array of photodetectors. The method may include capturing one or more images using a first focus setting for the image capture device; analyzing horizontal phase detection signals output from a first set of the multipole pixels while capturing the one or more images; analyzing vertical phase detection signals output from a second set of the multiple pixels while capturing the one or more images; and adjusting the first focus setting to a second focus setting based on the horizontal phase detection signal analysis and the vertical phase detection signal analysis. 
     In addition to the exemplary aspects and embodiments described above, further aspects and embodiments will become apparent by reference to the drawings and by study of the following description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosure will be readily understood by the following detailed description in conjunction with the accompanying drawings, wherein like reference numerals designate like structural elements, and in which: 
         FIGS. 1A-1B  show front and rear views of an electronic device that includes one or more image capture devices (e.g., cameras); 
         FIG. 2  shows an example embodiment of a camera, including an image sensor, a lens, and an auto-focus mechanism; 
         FIG. 3  shows an example of an image that may be captured by a camera; 
         FIG. 4  shows a plan view of one example of an image sensor; 
         FIG. 5  shows an example imaging area (e.g., a plan view) of a pixel in an image sensor; 
         FIG. 6  shows an example cross-section of the pixel shown in  FIG. 5 ; 
         FIG. 7  shows a simplified schematic of a pixel usable in an image sensor; 
         FIG. 8  shows a pixel configured for detection of horizontal edge focus; 
         FIG. 9  shows a pixel configured for detection of vertical edge focus; 
         FIG. 10A-10C  show an imaging area of an image sensor, in which the pixels of the image sensor are arranged in accordance with a Bayer pattern (i.e., a 2×2 pattern including red pixels and blue pixels along one diagonal, and green pixels along the other diagonal); 
         FIG. 11  shows a method of determining a focus setting for an image capture device that includes an image sensor having a plurality of pixels; and 
         FIG. 12  shows a sample electrical block diagram of an electronic device. 
     
    
    
     The use of cross-hatching or shading in the accompanying figures is generally provided to clarify the boundaries between adjacent elements and also to facilitate legibility of the figures. Accordingly, neither the presence nor the absence of cross-hatching or shading conveys or indicates any preference or requirement for particular materials, material properties, element proportions, element dimensions, commonalities of similarly illustrated elements, or any other characteristic, attribute, or property for any element illustrated in the accompanying figures. 
     Additionally, it should be understood that the proportions and dimensions (either relative or absolute) of the various features and elements (and collections and groupings thereof) and the boundaries, separations, and positional relationships presented therebetween, are provided in the accompanying figures merely to facilitate an understanding of the various embodiments described herein and, accordingly, may not necessarily be presented or illustrated to scale, and are not intended to indicate any preference or requirement for an illustrated embodiment to the exclusion of embodiments described with reference thereto. 
     DETAILED DESCRIPTION 
     Reference will now be made in detail to representative embodiments illustrated in the accompanying drawings. It should be understood that the following description is not intended to limit the embodiments to one preferred embodiment. To the contrary, it is intended to cover alternatives, modifications, and equivalents as can be included within the spirit and scope of the described embodiments as defined by the appended claims. 
     The present disclosure relates to an image capture device, pixel, and method of operating an image capture device or pixel, that provides improved PDAF performance for a device having a camera or other image capture device. 
     In some cases, PDAF pixels (i.e., pixels configured to collect PDAF information) may have a metal shield configuration. A metal shield pixel may include a microlens that focuses incoming light on a photodiode, which photodiode in turn converts photons into electron (or hole) pairs. The collected electrons (for electron collection devices) or holes (for hole collection devices) may be converted into an analog voltage through a pixel source follower (SF) transistor amplifier. The analog voltage may then be converted to a digital signal by an analog-to-digital converter (ADC). A metal shield (e.g., a Tungsten (W) or Copper/Aluminum (Cu/Al) metal shield) may cover half of the photodiode (e.g., a left half or a right half). For a left-shielded pixel, light from left-incident angles is blocked by the metal shield, and only light approaching the pixel from right-incident angles is received by the photodiode. A right-shielded pixel functions in the opposite manner. The angular sensitivity of left and right metal shield pixels can be used to generate PDAF information. 
     Because the signal (e.g., the analog voltage or digital signal) generated by a metal shield pixel will be much lower than the signal generated by an unshielded (or regular) pixel, metal-shielded pixels need to be treated as defective pixels, and their signals need to be corrected before being used to generate an image. To minimize the effect that signal correction may have on image quality, metal shield pixels (or pairs of left/right-shielded pixels) may be sparsely distributed over the surface of an image sensor. That is, a relatively small number of an image sensor&#39;s pixels (e.g., 3-4%) may be configured as left or right-shielded pixels. In one example, for every eight rows and eight columns of pixels (e.g., for every block of 64 pixels in a pixel array), one left-shielded pixel and one right-shielded pixel may be provided. 
     At a vertical edge within an image (e.g., at an edge defined by a perceptible edge between objects, or at an edge defined by different colors or brightness (e.g., an edge between dark and light regions)), left and right-shielded pixels will have disparate signals (e.g., signals not matched in magnitude and/or polarity) when an image is not in focus, but will have well-matched signals when an image is in focus. The signals of left and right-shielded pixels therefore provide PDAF information that can be used by an auto-focus (AF) mechanism to adjust the position of one or more optical components (e.g., a lens) or an image sensor, and thereby adjust the focus of an image on the image sensor. In some cases, an image may be brought into focus based on a PDAF information obtained during a single image capture frame. By analyzing PDAF information obtained during each image capture frame, images may be quickly and continuously focused on an image sensor. 
     In some embodiments, left and right-shielded pixels may be fabricated without metal shields by placing both pixels adjacent one another under a single microlens. Each pixel has its own photodiode, and there may be implant isolation or physical trench isolation between the photodiodes of the two pixels. Because of the nature (e.g., curvature) of the microlens, light from left-incident angles is received mainly by the left-side pixel, and light from right-incident angles is received mainly by the right-side pixel. As a result, left and right-side pixels placed adjacent one another under a single microlens may function similarly to left and right metal shielded pixels. In a Bayer pattern pixel configuration (i.e., a repetitive 2×2 pattern including red pixels and blue pixels along one diagonal, and green pixels along the other diagonal), one blue pixel in every 8×8 block of pixels may be replaced by a green pixel (or may be modified to function as a green pixel), so that two adjacent green pixels may be placed under a single microlens to provide PDAF information. The signals of both pixels need to be corrected before being used to generate an image. 
     Because the signals provided by metal shield pixels, or the signals provided by adjacent pixels under a microlens, need to be corrected before being used to generate an image, the density of such pixels may be kept low. However, this provides limited PDAF information, which in turn degrades AF performance (especially in low light conditions). To improve PDAF performance, each pixel in a pixel array may be divided into left and right sub-pixels, and PDAF information may be obtained from each pixel. Also, because all pixels are implemented in a similar manner, the sub-pixel signals for each pixel may be combined in a similar way, or signal corrections may be made to each pixel in a similar way, to increase the confidence level that pixel signals are being generated or corrected appropriately (especially in low light conditions). However, the PDAF information provided by such a pixel array (and by all pixel arrays using metal shield pixels or adjacent pixels under a single microlens) bases image focus entirely on vertical edges. For an image containing few vertical edges or more horizontal edges, or for an image acquired under a low light condition, PDAF performance may suffer. For example, it may be difficult or impossible to focus an image on an image sensor, or it may take longer than desired to focus an image on an image sensor. 
     The present disclosure describes a pixel having a 2×2 array of sub-pixels (e.g., photodetectors) disposed under a microlens. In some embodiments, the entirety of a pixel array may incorporate such pixels. The pixels can be used, in various embodiments or configurations, to provide PDAF information based on edges having more than one orientation (e.g., vertical and horizontal edges), to improve PDAF performance (especially in low light conditions), to reduce or eliminate the need for signal correction, or to increase the resolution of an image sensor. 
     In one embodiment, a pixel described herein may include an imaging area and a microlens, and may be associated with a set of charge transfer transistors and a shared readout circuit. The imaging area may include a two-dimensional array of photodetectors, with each photodetector (or each photodetector in a subset of photodetectors) being electrically isolated from each other photodetector. The microlens may be disposed over the array of photodetectors. The shared readout circuit may be associated with the array of photodetectors, and each charge transfer transistor may be operable to connect a photodetector in the array of photodetectors to the shared readout circuit. In some examples, charge integrated by two or four photodetectors may be read out of the pixel simultaneously and summed by the shared readout circuit. In some examples, charge integrated by different pairs of photodetectors may be read out of the pixel sequentially. In some examples, the pair of photodetectors for which charge is read out and summed may be reconfigured between image capture frames. In some examples, the charge integrated by each photodetector of the pixel may be independently read, or the charge integrated by all photodetectors of the pixel may be read out and summed. 
     These and other embodiments are discussed below with reference to  FIGS. 1-12 . However, those skilled in the art will readily appreciate that the detailed description given herein with respect to these figures is for explanatory purposes only and should not be construed as limiting. 
     Directional terminology, such as “top”, “bottom”, “front”, “back”, “over”, “under”, “left”, “right”, etc. is used with reference to the orientation of some of the components in some of the figures described below. Because components in various embodiments can be positioned in a number of different orientations, directional terminology is used for purposes of illustration only and is in no way limiting. The directional terminology is intended to be construed broadly, and therefore should not be interpreted to preclude components being oriented in different ways. 
     Referring now to  FIGS. 1A-1B , there are shown front and rear views of an electronic device  100  that includes one or more image capture devices (e.g., cameras). The electronic device  100  includes a first camera  102 , a second camera  104 , an enclosure  106 , a display  110 , an input/output (I/O) member  108 , and a flash  112  or light source for the second camera  104 . Each of the first camera  102  and second camera  104  may be associated with a respective image sensor. The electronic device  100  may also include one or more internal components (not shown) typical of a computing or electronic device, such as, for example, one or more processors, memory components, network interfaces, and so on. 
     In the illustrated embodiment, the electronic device  100  is implemented as a smartphone. Other embodiments, however, are not limited to this construction. Other types of computing or electronic devices which may include a camera or image sensor include, but are not limited to, a netbook or laptop computer, a tablet computer, a digital camera, a scanner, a video recorder, a watch (or other wearable electronic device), a drone, a vehicle navigation system, and so on. 
     As shown in  FIGS. 1A-1B , the enclosure  106  may form an outer surface or partial outer surface and protective case for the internal components of the electronic device  100 , and may at least partially surround the display  110 . The enclosure  106  may be formed of one or more components operably connected together, such as a front piece and a back piece. Alternatively, the enclosure  106  may be formed of a single piece operably connected to the display  110 . 
     The I/O member  108  may be implemented with any type of input or output member. By way of example only, the I/O member  108  may be a switch, a button, a capacitive sensor, or other input mechanism. The I/O member  108  allows a user to interact with the electronic device  100 . For example, the I/O member  108  may be a button or switch to alter the volume, return to a home screen, and the like. The electronic device may include one or more input members or output members, and each member may have a single input, output, or I/O function, or some members may have multiple I/O functions. In some embodiments, the I/O member  108  may be incorporated into the display  110 , the first camera  102 , or an audio I/O member. 
     The display  110  may be operably or communicatively connected to the electronic device  100 . The display  110  may be implemented as any suitable type of display, such as a high resolution display or an active matrix color liquid crystal display (LCD). The display  110  may provide a visual output for the electronic device  100  or function to receive user inputs to the electronic device  100  (or provide user outputs from the electronic device  100 ). For example, the display  110  may display images captured by the first camera  102  or the second camera  104 . In some embodiments, the display  110  may include a multi-touch capacitive sensing touchscreen that is operable to detect one or more user inputs. 
       FIG. 2  shows an example embodiment of an image capture device (e.g., a camera  200 ), including an image sensor  202 , a lens  204 , and an auto-focus mechanism  206 . In some embodiments, the components shown in  FIG. 2  may be associated with the first camera  102  or the second camera  104  shown in  FIGS. 1A-1B . 
     The image sensor  202  may include a plurality of pixels, such as a plurality of pixels arranged in a two-dimensional array. Multiple ones (or all) of the pixels may each include a two-dimensional array of sub-pixels (e.g., a 2×2 array of sub-pixels), with each sub-pixel including a photodetector. Having a majority (or more significantly at least 80%, and preferably all) of the pixels configured to include a 2×2 array of sub-pixels can help improve PDAF performance and/or reduce or eliminate the need to correct the outputs of PDAF-capable pixels in relation to the outputs of other pixels. The sub-pixels (or photodetectors) associated with a pixel may be electrically isolated from each other, but disposed under a shared microlens for the pixel. 
     The lens  204  may be adjustable with respect to the image sensor  202 , to focus an image of a scene  208  on the image sensor  202 . In some embodiments, the lens  204  may be moved with respect to the image sensor  202  (e.g., moved to change a distance between the lens  204  and the image sensor  202 , moved to change an angle between a plane of the lens  204  and a plane of the image sensor  202 , and so on). In other embodiments, the image sensor  202  may be moved with respect to the lens  204 . 
     In some embodiments, the auto-focus mechanism  206  may include (or the functions of the auto-focus mechanism  206  may be provided by) a processor. The auto-focus mechanism  206  may receive signals from the image sensor  202  and, in response to the signals, adjust a focus setting of the camera  200 . In some embodiments, the signals may include PDAF information. The PDAF information may include both horizontal phase detection signals and vertical phase detection signals. In response to the PDAF information (e.g., in response to an out-of-focus condition identified from the PDAF information), the auto-focus mechanism  206  may adjust a focus setting of the camera  200  by, for example, adjusting a relationship between the image sensor  202  (or plurality of pixels) and the lens  204  (e.g., by adjusting a physical position of the lens  204  or the image sensor  202 ). 
     Referring now to  FIG. 3 , there is shown an example of an image  300  that may be captured by an image capture device, such as one of the cameras described with reference to  FIG. 1A-1B or 2 . The image  300  may include a number of objects  302 ,  304  having edges  306 ,  308  oriented in one or more directions. The edges  306 ,  308  may include perceptible edges between objects, or edges defined by different colors or brightness (e.g., an edge between dark and light regions). In some embodiments, the camera may detect a focus of both a first set of edges (e.g., horizontal edges) and a second set of edges (e.g., vertical edges, or edges that are orthogonal to the first set of edges). 
     The focus of the first and second sets of edges may be detected in the same or different image capture frames, using the same or different pixels. In some cases, a focus of edges in the first set of edges may be detected using a first subset of pixels configured to detect a focus of horizontal edges, in a same frame that a focus of edges in the second set of edges is detected by a second subset of pixels configured to detect a focus of vertical edges. In another frame, a focus of edges in the second set of edges may be detected by the first subset of pixels, and a focus of edges in the first set of edges may be detected by the second subset of pixels. In other cases, a focus of edges in the first set may be detected by up to all of the pixels in an image sensor in a first image capture frame, and a focus of edges in the second set may be detected by up to all of the pixels in the image sensor in a second image capture frame. A focus of edges may be detected based on a phase difference (e.g., magnitude and polarity of the phase difference) in light captured by different sub-pixels (e.g., different photodetectors) associated with a pixel. 
     In some embodiments, a single pixel in a pixel array (and in some cases, some or each of the pixels in the pixel array, or each of the pixels in a subset of pixels in the pixel array) may be reconfigured between image capture frames, or at other times, to produce a signal usable for detecting the focus of a horizontal edge, a vertical edge, or a diagonal edge. In some embodiments, all of the pixels in a pixel array (or all of the pixels used to capture a particular image) may be employed in the detection of edge focus information for an image. 
       FIG. 4  shows a plan view of one example of an image sensor  400 , such as an image sensor associated with one of the image capture devices or cameras described with reference to  FIGS. 1A-1B and 2 . The image sensor  400  may include an image processor  402  and an imaging area  404 . The imaging area  404  may be implemented as a pixel array that includes a plurality of pixels  406 . The pixels  406  may be same colored pixels (e.g., for a monochrome imaging area  404 ) or differently colored pixels (e.g., for a multi-color imaging area  404 ). In the illustrated embodiment, the pixels  406  are arranged in rows and columns. However, other embodiments are not limited to this configuration. The pixels in a pixel array may be arranged in any suitable configuration, such as, for example, a hexagonal configuration. 
     The imaging area  404  may be in communication with a column select circuit  408  through one or more column select lines  410 , and with a row select circuit  412  through one or more row select lines  414 . The row select circuit  412  may selectively activate a particular pixel  406  or group of pixels, such as all of the pixels  406  in a certain row. The column select circuit  408  may selectively receive the data output from a selected pixel  406  or group of pixels  406  (e.g., all of the pixels in a particular row). 
     The row select circuit  412  and/or column select circuit  408  may be in communication with an image processor  402 . The image processor  402  may process data from the pixels  406  and provide that data to another processor (e.g., a system processor) and/or other components of a device (e.g., other components of the electronic device  100 ). In some embodiments, the image processor  402  may be incorporated into the system. The image processor  402  may also receive focus information (e.g., PDAF information) from some or all of the pixels, and may perform a focusing operation for the image sensor  400 . In some examples, the image processor  402  may perform one or more of the operations performed by the auto-focus mechanism described with reference to  FIG. 2 . 
       FIG. 5  shows an example imaging area (e.g., a plan view) of a pixel  500  in an image sensor, such as a pixel included in an image sensor associated with one of the image capture devices or cameras described with reference to  FIGS. 1A-1B and 2 , or a pixel included in the image sensor described with reference to  FIG. 4 . In some embodiments, some pixels in an image sensor, each pixel in an image sensor, or each pixel in a subset of pixels in an image sensor, may be configured as shown in  FIG. 5 . 
     The imaging area of the pixel  500  includes a two-dimensional array of photodetectors  502  or sub-pixels (e.g., an array of sub-pixels, with each sub-pixel including a photodetector  502 ). In some embodiments, the imaging area may include a 2×2 array of sub-pixels or photodetectors (e.g., a set of photodetectors  502  arranged in two rows and two columns). For example, the array may include a first photodetector  502   a  and a second photodetector  502   b  arranged in a first row, and a third photodetector  502   c  and a fourth photodetector  502   d  arranged in a second row. The first photodetector  502   a  and the third photodetector  502   c  may be arranged in a first column, and the second photodetector  502   b  and the fourth photodetector  502   d  may be arranged in a second column. 
     Each photodetector  502  may be electrically isolated from each other photodetector  502  (e.g., by implant isolation or physical trench isolation). A microlens  504  may be disposed over the array of photodetectors  502 . An optional same color light filter (e.g., a red filter, a blue filter, a green filter, or the like) may also be disposed over the array of photodetectors  502 . In some examples, the light filter may be applied to an interior or exterior of the microlens  504 . In some examples, the microlens may be tinted to provide the light filter. In some examples, each of the photodetectors may be separately encapsulated under the microlens  504 , and the light filter may be applied to or in the encapsulant. In some examples, a light filter element may be positioned between the photodetectors  502  and the microlens  504  (although other configurations of the light filter may also be considered as being disposed “between” the photodetectors  502  and the microlens  504 ). 
     The photodetectors  502  may be connected to a shared readout circuit (i.e., a readout circuit shared by all of the photodetectors  502  associated with the pixel  500 ). A set of charge transfer transistors may be operable to connect the photodetectors  502  to the shared readout circuit (e.g., each charge transfer transistor in the set may be operable (e.g., by a processor) to connect a respective one of the photodetectors  502  to, and disconnect the respective one of the photodetectors  502  from, the shared readout circuit; alternatively, a charge transfer transistor may be statically configured to connect/disconnect a pair of the photodetectors  502  to/from the shared readout circuit). In some cases, each charge transfer transistor may be operated individually. In other cases, the charge transfer transistors may be statically configured for pair-wise operation. 
       FIG. 6  shows an example cross-section of the pixel  500  shown in  FIG. 5 . By way of example, the cross-section is taken through the first row of photodetectors  502  shown in  FIG. 5 . Cross-sections through the second row, the first column, and the second column may be configured similarly to the cross-section shown in  FIG. 6 . 
     A first sub-pixel  600   a  may include the photodetector  502   a , and a second sub-pixel  600   b  may include the photodetector  502   b . The first and second photodetectors  502   a ,  502   b  may be formed in a substrate  602 . The substrate  602  may include a semiconductor-based material, such as, but not limited to, silicon, silicon-on-insulator (SOI), silicon-on-sapphire (SOS), doped and undoped semiconductor regions, epitaxial layers formed on a semiconductor substrate, well regions or buried layers formed in a semiconductor substrate, or other semiconductor structures. 
     The microlens  504  may be disposed over part or all of both of the photodetectors  502   a ,  502   b  (as well as part or all of the photodetectors  502   c  and  502   d ). The microlens  504  may be formed of any material or combination of materials that is translucent to at least one wavelength of light. The microlens may have a light-receiving side  612  opposite the array of photodetectors  502 . The light-receiving side  612  of the microlens  504  may include a central portion  608  and a peripheral portion  610 . The peripheral portion  610  may be configured to redirect at least a portion of light incident on the peripheral portion (e.g., the light  606   a  or light  606   c ) toward a corresponding peripheral portion of the imaging area that includes the photodetectors  502  (e.g., the light  606   a  may be redirected toward the photodetector  502   a , and the light  606   c  may be redirected toward the photodetector  502   b ). In some embodiments, the microlens  504  may have a convex-shaped or dome-shaped light-receiving surface (or exterior surface). 
     The microlens  504  may be configured to focus incident light  606  received from different angles on different ones or both of the photodetectors  502   a ,  502   b . For example, light  606   a  incident on the microlens  504  from a left side approach angle may be focused more (or solely) on the left side photodetector  502   a , and thus the left side photodetector  502   a  may accumulate more charge than the right side photodetector  502   b , making the signal response of the left side sub-pixel  600   a  greater than the signal response of the right side sub-pixel  600   b . Similarly, light  606   c  incident on the microlens  504  from a right side approach angle may be focused more (or solely) on the right side photodetector  502   b , and thus the right side photodetector  502   b  may accumulate more charge than the left side photodetector  502   a , making the signal response of the right side sub-pixel  600   b  greater than the signal response of the left side sub-pixel  600   a . Light  606   b  incident on the microlens  504  from the front center (or top) of the microlens  504  may be focused on both of the photodetectors  502   a ,  502   b , making the signal response of the left and right side sub-pixels  600   a ,  600   b  about equal. 
     An optional same color light filter  604  (e.g., a red filter, a blue filter, a green filter, or the like) may be disposed over each of the photodetectors  502   a ,  502   b  (as well as the photodetectors  502   c  and  502   d ). 
     Referring now to  FIG. 7 , there is shown a simplified schematic of a pixel  700  (and associated shared readout circuit  704 ) usable in an image sensor. In some embodiments, the pixel  700  may be an example of a pixel included in an image sensor associated with one of the image capture devices or cameras described with reference to  FIGS. 1A-1B and 2 , or a pixel included in the image sensor described with reference to  FIG. 4 , or the pixel described with reference to  FIGS. 5-6 . In some embodiments, some pixels in an image sensor, each pixel in an image sensor, or each pixel in a subset of pixels in an image sensor, may be configured as shown in  FIG. 7 , and the shared readout circuit  704  for the pixel  700  may be part of an overall pixel readout circuit for an image sensor. 
     The pixel  700  may include a two-dimensional array of photodetectors  702 , with each photodetector  702  being selectively connectable to (and disconnectable from) the shared readout circuit  704  by a respective charge transfer transistor in a set of charge transfer transistors  706 . In some embodiments, the two-dimensional array of photodetectors  702  may include a 2×2 array of photodetectors (e.g., an array of photodetectors  702  arranged in two rows and two columns). For example, the array may include a first photodetector  702   a  (PD_TL) and a second photodetector  702   b  (PD_TR) arranged in a first row, and a third photodetector  702   c  (PD_BL) and a fourth photodetector  702   d  (PD_BR) arranged in a second row. The first photodetector  702   a  and the third photodetector  702   c  may be arranged in a first column, and the second photodetector  702   b  and the fourth photodetector  702   d  may be arranged in a second column. As described with reference to  FIGS. 5 and 6 , the photodetectors  702  may be disposed (positioned) in a 2×2 array under a microlens. 
     The shared readout circuit  704  may include a sense region  708 , a reset (RST) transistor  710 , a readout transistor  712 , and a row select (RS) transistor  714 . The sense region  708  may include a capacitor that temporarily stores charge received from one or more of the photodetectors  702 . As described below, charge accumulated by one or more of the photodetectors  702  may be transferred to the sense region  708  by applying a drive signal (e.g., a gate voltage) to one or more of the charge transfer transistors  706 . The transferred charge may be stored in the sense region  708  until a drive signal applied to the reset (RST) transistor  710  is pulsed. 
     Each of the charge transfer transistors  706  may have one terminal connected to a respective one of the photodetectors  702  and another terminal connected to the sense region  708 . One terminal of the reset transistor  710  and one terminal of the readout transistor  712  may be connected to a supply voltage (e.g., VDD)  514 . The other terminal of the reset transistor  710  may be connected to the sense region  708 , while the other terminal of the readout transistor  712  may be connected to a terminal of the row select transistor  714 . The other terminal of the row select transistor  714  may be connected to an output line  716 . 
     By way of example only, and in one embodiment, each of the photodetectors  702  may be implemented as a photodiode (PD) or pinned photodiode, the sense region  708  may be implemented as a floating diffusion (FD) node, and the readout transistor  712  may be implemented as a source follower (SF) transistor. The photodetectors  702  may be electron-based photodiodes or hole-based photodiodes. The term photodetector is used herein to refer to substantially any type of photon or light detecting component, such as a photodiode, pinned photodiode, photogate, or other photon sensitive region. Additionally, the term sense region, as used herein, is meant to encompass substantially any type of charge storing or charge converting region. 
     In some embodiments, the pixel  700  may be implemented using additional or different components. For example, the row select transistor  714  may be omitted and a pulsed power supply may be used to select the pixel. 
     When an image is to be captured, an integration period for the pixel begins and the photodetectors  702  accumulate photo-generated charge in response to incident light. When the integration period ends, the accumulated charge in some or all of the photodetectors  702  may be transferred to the sense region  708  by sequentially or simultaneously applying drive signals to (e.g., by pulsing gate voltages of) the charge transfer transistors  706 . Typically, the reset transistor  710  is used to reset the voltage on the sense region  708  to a predetermined level prior to the transfer of charge from a set of one or more photodetectors  702  to the sense region  708 . When charge is to be read out of the pixel  700 , a drive signal may be applied to the row select transistor  714  (e.g., a gate voltage of the row select transistor  714  may be pulsed) via a row select line  718  coupled to row select circuitry, and charge from one, two, or any number of the photodetectors  702  may be read out over an output line  716  coupled to column select circuitry. The readout transistor  712  senses the voltage on the sense region  708 , and the row select transistor  714  transfers an indication of the voltage to the output line  716 . The column select circuitry may be coupled to an image processor, auto-focus mechanism, or combination thereof. 
     In some embodiments, a processor may be configured to operate the set of charge transfer transistors  706  to simultaneously transfer charge from multiple photodetectors  702  (e.g., a pair of photodetectors) to the sense region  708  or floating diffusion node. For example, the gates of first and second charge transfer transistors  706   a  (TX_A) and  706   b  (TX_B) (i.e., the charge transfer transistors of the first row) may be simultaneously driven to transfer charges accumulated by the first and second photodetectors  702   a ,  702   b  to the sense region  708 , where the charges may be summed. After reading the summed charge out of the pixel  700 , the gates of third and fourth charge transfer transistors  706   c  (TX_C) and  706   d  (TX_D) (i.e., the charge transfer transistors of the second row) may be simultaneously driven to transfer charges accumulated by the third and fourth photodetectors  702   c ,  702   d  to the sense region  708 , where the charges may be summed. This summed charge may also be read out of the pixel  700 . In a subsequent frame of image capture, the gates of the first and third charge transfer transistors  706   a  and  706   c  (i.e., the charge transfer transistors of the first column) may be simultaneously driven to transfer charges accumulated by the first and third photodetectors  702   a ,  702   c  to the sense region  708 . After reading this charge out of the pixel  700 , the gates of the second and fourth charge transfer transistors  706   b  and  706   d  (i.e., the charge transfer transistors of the second column) may be simultaneously driven to transfer charges accumulated by the second and fourth photodetectors  702   b ,  702   d  to the sense region  708 . This charge may also be read out of the pixel  700 . Additionally or alternatively, charge accumulated by the photodetectors  702  may be read out of the pixel  700  individually, or charges accumulated by any combination (including all) of the photodetectors  702  may be read out of the pixel  700  together, or charges accumulated by the photodetectors  702  along a left or right-sloping diagonal may be read out of the pixel  700  together. 
     When charges accumulated by different photodetectors  702  are read out of the pixel  700  individually, the charges may be summed in various ways, or a processor may interpolate between the values read out of the same colored sub-pixels in different pixels of a pixel array to generate an image having an effective 4× resolution for the pixel array. 
     In some embodiments, a shared readout circuit per pixel may be configured differently for different pixels in a pixel array. For example, in a potentially lower cost image sensor, or in an image sensor implemented using front side illumination (FSI) technology, a single charge transfer transistor may be coupled to a pair of photodetectors, and may be operated by a processor to simultaneously read charges out of, and sum charges, integrated by a pair of photodetectors. For example, in one pixel of an image sensor, a single charge transfer transistor could replace both of the charge transfer transistors  706   a  and  706   b  and connect both of the photodiodes  702   a  and  702   b  to the shared readout circuit  704 , and another charge transfer transistor could replace both of the charge transfer transistors  706   c  and  706   d  and connect both of the photodiodes  702   c  and  702   d  to the shared readout circuit  704 . Similarly, in another pixel of the image sensor, a single charge transfer transistor could replace both of the charge transfer transistors  706   a  and  706   c  and connect both of the photodiodes  702   a  and  702   c  to the shared readout circuit  704 , and another charge transfer transistor could replace both of the charge transfer transistors  706   b  and  706   d  and connect both of the photodiodes  702   b  and  702   d  to the shared readout circuit  704 . 
     In some embodiments, an image capture device, such as a camera, may not include a shutter, and thus an image sensor of the image capture device may be constantly exposed to light. When the pixel  700  is used in these embodiments, the photodetectors  702  may have to be reset or depleted of charge before an image is captured (e.g., by applying drive signals (e.g., gate voltages) to the reset transistor  710  and charge transfer transistors  706 ). After the charge from the photodetectors  702  has been depleted, the charge transfer transistors  706  and reset transistor  710  may be turned off to isolate the photodetectors  702  from the shared readout circuit  704 . The photodetectors  702  can then accumulate photon-generated charge during a charge integration period. 
       FIG. 8  shows a pixel  800  configured for detection of horizontal edge focus. The pixel  800  may be an example of a pixel included in an image sensor associated with one of the image capture devices or cameras described with reference to  FIGS. 1A-1B and 2 , or a pixel included in the image sensor described with reference to  FIG. 4 , or the pixel described with reference to any of  FIGS. 5-7 . 
     The imaging area of the pixel  800  includes a two-dimensional array of photodetectors  802  or sub-pixels (e.g., an array of sub-pixels with each sub-pixel including a photodetector  802 ). For example, the array may include a first photodetector  802   a  and a second photodetector  802   b  arranged in a first row, and a third photodetector  802   c  and a fourth photodetector  802   d  arranged in a second row. The first photodetector  802   a  and the third photodetector  802   c  may be arranged in a first column, and the second photodetector  802   b  and the fourth photodetector  802   d  may be arranged in a second column. 
     Each photodetector  802  may be electrically isolated from each other photodetector  802  (e.g., by implant isolation or physical trench isolation). A microlens  804  may be disposed over the array of photodetectors  802 . An optional same color light filter (e.g., a red filter, a blue filter, a green filter, or the like) may also be disposed over the array of photodetectors  802 . 
     The photodetectors  802  may be connected to a shared readout circuit (i.e., a readout circuit shared by all of the photodetectors  802  associated with the pixel  800 , as described, for example, with reference to  FIG. 7 ). A set of charge transfer transistors may be operable to connect the photodetectors  802  to the shared readout circuit (e.g., each charge transfer transistor in the set may be operable (e.g., by a processor) to connect a respective one of the photodetectors  802  to, and disconnect the respective one of the photodetectors  802  from, the shared readout circuit). In some cases, each charge transfer transistor may be operated individually. 
     As indicated by the broken lines  806   a  and  806   b , the charge transfer transistors may be operated (e.g., by a processor) to read a sum of the charges accumulated by the first and second photodetectors  802   a ,  802   b  out of the pixel  800 , and then operated to read a sum of the charges accumulated by the third and fourth photodetectors  802   c ,  802   d  out of the pixel  800 . In some embodiments, the summed charges may be compared to detect a phase difference in the charges, and to perform a PDAF operation based on horizontal edge focus detection. The summed charges may also or alternatively summed to obtain a pixel value. In some embodiments, the summed charges may be summed without correction to obtain the pixel value. 
       FIG. 9  shows a pixel  900  configured for detection of vertical edge focus. The pixel  900  may be an example of a pixel included in an image sensor associated with one of the image capture devices or cameras described with reference to  FIGS. 1A-1B and 2 , or a pixel included in the image sensor described with reference to  FIG. 4 , or the pixel described with reference to any of  FIGS. 5-8 . 
     The imaging area of the pixel  900  includes a two-dimensional array of photodetectors  902  or sub-pixels (e.g., an array of sub-pixels with each sub-pixel including a photodetector  902 ). For example, the array may include a first photodetector  902   a  and a second photodetector  902   b  arranged in a first row, and a third photodetector  902   c  and a fourth photodetector  902   d  arranged in a second row. The first photodetector  902   a  and the third photodetector  902   c  may be arranged in a first column, and the second photodetector  902   b  and the fourth photodetector  902   d  may be arranged in a second column. 
     Each photodetector  902  may be electrically isolated from each other photodetector  902  (e.g., by implant isolation or physical trench isolation). A microlens  904  may be disposed over the array of photodetectors  902 . An optional same color light filter (e.g., a red filter, a blue filter, a green filter, or the like) may also be disposed over the array of photodetectors  902 . 
     The photodetectors  902  may be connected to a shared readout circuit (i.e., a readout circuit shared by all of the photodetectors  902  associated with the pixel  900 , as described, for example, with reference to  FIG. 7 ). A set of charge transfer transistors may be operable to connect the photodetectors  902  to the shared readout circuit (e.g., each charge transfer transistor in the set may be operable (e.g., by a processor) to connect a respective one of the photodetectors  902  to, and disconnect the respective one of the photodetectors  902  from, the shared readout circuit). In some cases, each charge transfer transistor may be operated individually. 
     As indicated by the broken lines  906   a  and  906   b , the charge transfer transistors may be operated (e.g., by a processor) to read a sum of the charges accumulated by the first and third photodetectors  902   a ,  902   c  out of the pixel  900 , and then operated to read a sum of the charges accumulated by the second and fourth photodetectors  902   b ,  902   d  out of the pixel  900 . In some embodiments, the summed charges may be compared to detect a phase difference in the charges, and to perform a PDAF operation based on vertical edge focus detection. The summed charges may also or alternatively summed to obtain a pixel value. In some embodiments, the summed charges may be summed without correction to obtain the pixel value. In some embodiments, a single pixel may be configured as shown in  FIG. 8  for one image capture frame, and configured as shown in  FIG. 9  for another image capture frame. 
       FIGS. 10A-10C  show an imaging area  1000  of an image sensor, in which the pixels  1002  of the image sensor are arranged in accordance with a Bayer pattern (i.e., a 2×2 pattern including red pixels and blue pixels along one diagonal, and green pixels along the other diagonal). The pixels  1002  may be arranged in Bayer pattern rows  1006   a ,  1006   b  and Bayer pattern columns  1008   a ,  1008   b .  FIGS. 10A-10C  also show each pixel  1002  as having a 2×2 array of sub-pixels  1004 , with each sub-pixel  1004  including a photodetector, as described, for example, with reference to  FIG. 5-9 .  FIGS. 10A-10C  show different ways in which the readout circuits for the pixels  1002  may be configured during an image capture frame. In some embodiments, the imaging area  1000  may be an example of an imaging area of an image sensor associated with one of the image capture devices or cameras described with reference to  FIGS. 1A-1B and 2 , or the imaging area of the image sensor described with reference to  FIG. 4 , or an imaging area including a plurality of the pixels described with reference to any of  FIGS. 5-9 . 
     In  FIG. 10A , the pixels  1002  in the first Bayer pattern row  1006   a  of the imaging area  1000  are configured (or are operable) to detect a phase difference (e.g., an out-of-focus condition) in a first set of edges of an image (e.g., vertical edges), and the pixels  1002  in the second Bayer pattern row  1006   b  are configured (or are operable) to detect a phase difference in a second set of edges of the image (e.g., horizontal edges, or edges that are otherwise orthogonal to the first set of edges). The configuration shown in  FIG. 10A  may be useful in that it simplifies signal routing per Bayer pattern row  1006 . However, improved PDAF performance is only achieved by column. 
     In  FIG. 10B , the pixels  1002  in the first Bayer pattern column  1008   a  of the imaging area  1000  are configured (or are operable) to detect a phase difference (e.g., an out-of-focus condition) in a first set of edges of an image (e.g., vertical edges), and the pixels  1002  in the second Bayer pattern column  1008   b  are configured (or are operable) to detect a phase difference in a second set of edges of the image (e.g., horizontal edges, or edges that are otherwise orthogonal to the first set of edges). The configuration shown in  FIG. 10BA  may be useful in that it simplifies signal routing per Bayer pattern column  1008 . However, improved PDAF performance is only achieved by row. 
     In  FIG. 10C , a first set of the pixels  1002  in each Bayer pattern row  1006  and Bayer pattern column  1008  of the imaging area  1000  is configured (or is operable) to detect a phase difference (e.g., an out-of-focus condition) in a first set of edges of an image (e.g., vertical edges), and a second set of the pixels  1002  in the each Bayer pattern row  1006  and Bayer pattern column  1008  is configured (or is operable) to detect a phase difference in a second set of edges of the image (e.g., horizontal edges, or edges that are otherwise orthogonal to the first set of edges). The configuration shown in  FIG. 10C  may be useful in that it improves PDAF performance by row and column. However, signal routing is more complex over the configurations described with reference to  FIGS. 10A-10B . 
     Pixels and pixel arrays configured as described in the present disclosure may be implemented using back side illumination (BSI) technology or FSI technology, though a BSI implementation may provide more metal routing options and better enable the charge collected by each sub-pixel of a pixel to be separately read out of a pixel. When metal routing options are limited, a particular pixel in a pixel array may be statically configured as a horizontal edge detection PDAF pixel or a vertical edge detection PDAF pixel. 
     Referring now to  FIG. 11 , there is shown a method  1100  of determining a focus setting for an image capture device that includes an image sensor having a plurality of pixels. Some or all of the pixels (e.g., each pixel of multiple pixels) may include a two-dimensional array of photodetectors disposed under a microlens, with each photodetector of the array of photodetectors being electrically isolated from each other photodetector in the array of photodetectors. In some embodiments, the method  1100  may be performed by one of the image capture devices or cameras described with reference to  FIGS. 1A-1B and 2 , or an image capture device or camera including the image sensor described with reference to any of  FIGS. 4 and 10A-10C , or an image capture device or camera including a plurality of the pixels described with reference to any of  FIGS. 5-9 . 
     At  1102 , the method  1100  may include capturing one or more images using a first focus setting for the image capture device. The operation(s) at  1102  may be performed, for example, by the auto-focus mechanism described with reference to  FIG. 2 , the image processor described with reference to  FIG. 4 , or the processor or image processor described with reference to  FIG. 12 . 
     At  1104 , the method  1100  may include analyzing horizontal phase detection signals output from a first set of the multiple pixels while capturing the one or more images. The operation(s) at  1104  may be performed, for example, by the auto-focus mechanism described with reference to  FIG. 2 , the image processor described with reference to  FIG. 4 , or the processor or image processor described with reference to  FIG. 12 . 
     At  1106 , the method  1100  may include analyzing vertical phase detection signals output from a second set of the multiple pixels while capturing the one or more images. The operation(s) at  1106  may be performed, for example, by the auto-focus mechanism described with reference to  FIG. 2 , the image processor described with reference to  FIG. 4 , or the processor or image processor described with reference to  FIG. 12 . 
     At  1108 , the method  1100  may include adjusting the first focus setting to a second focus setting based on the horizontal phase detection signal analysis and the vertical phase detection signal analysis. The operation(s) at  1108  may be performed, for example, by the auto-focus mechanism described with reference to  FIG. 2 , the image processor described with reference to  FIG. 4 , or the processor or image processor described with reference to  FIG. 12 . 
     In some embodiments of the method  1100 , each of the first set of multiple pixels and the second set of multiple pixels may include the plurality of pixels (i.e., all of the pixels in the imaging area). In some embodiments of the method  1100 , at least a first subset of the horizontal phase detection signals and at least a first subset of the vertical phase detection signals may be acquired in a single image capture frame (i.e., while capturing one images). 
     In some embodiments, the method  1100  may include modifying a pairing of photodetectors of at least one pixel in the multiple pixels (e.g., modifying a sub-pixel pairing of at least one pixel in the multiple pixels). The modification may occur between a first image capture frame and a second image capture (i.e., between capturing a first image and a second image). The pairing of photodetectors may determine a charge summing that occurs during a read out of charges accumulated by a pixel. 
       FIG. 12  shows a sample electrical block diagram of an electronic device  1200 , which may be the electronic device described with reference to  FIG. 1 . The electronic device  1200  may include a display  1202  (e.g., a light-emitting display), a processor  1204 , a power source  1206 , a memory  1208  or storage device, a sensor  1210 , and an input/output (I/O) mechanism  1212  (e.g., an input/output device and/or input/output port). The processor  1204  may control some or all of the operations of the electronic device  1200 . The processor  1204  may communicate, either directly or indirectly, with substantially all of the components of the electronic device  100 . For example, a system bus or other communication mechanism  1214  may provide communication between the processor  1204 , the power source  1206 , the memory  1208 , the sensor  1210 , and/or the input/output mechanism  1212 . 
     The processor  1204  may be implemented as any electronic device capable of processing, receiving, or transmitting data or instructions. For example, the processor  1204  may be a microprocessor, a central processing unit (CPU), an application-specific integrated circuit (ASIC), a digital signal processor (DSP), or combinations of such devices. As described herein, the term “processor” is meant to encompass a single processor or processing unit, multiple processors, multiple processing units, or other suitably configured computing element or elements. 
     It should be noted that the components of the electronic device  1200  may be controlled by multiple processors. For example, select components of the electronic device  1200  may be controlled by a first processor and other components of the electronic device  1200  may be controlled by a second processor, where the first and second processors may or may not be in communication with each other. 
     The power source  1206  may be implemented with any device capable of providing energy to the electronic device  1200 . For example, the power source  1206  may be one or more batteries or rechargeable batteries. Additionally or alternatively, the power source  1206  may be a power connector or power cord that connects the electronic device  1200  to another power source, such as a wall outlet. 
     The memory  1208  may store electronic data that may be used by the electronic device  1200 . For example, the memory  1208  may store electrical data or content such as, for example, audio and video files, documents and applications, device settings and user preferences, timing signals, control signals, data structures or databases, image data, or focus settings. The memory  1208  may be configured as any type of memory. By way of example only, the memory  1208  may be implemented as random access memory, read-only memory, Flash memory, removable memory, other types of storage elements, or combinations of such devices. 
     The electronic device  1200  may also include one or more sensors  1210  positioned substantially anywhere on the electronic device  1200 . The sensor(s)  1210  may be configured to sense substantially any type of characteristic, such as but not limited to, pressure, light, touch, heat, movement, relative motion, biometric data, and so on. For example, the sensor(s)  1210  may include a heat sensor, a position sensor, a light or optical sensor, an accelerometer, a pressure transducer, a gyroscope, a magnetometer, a health monitoring sensor, and so on. Additionally, the one or more sensors  1210  may utilize any suitable sensing technology, including, but not limited to, capacitive, ultrasonic, resistive, optical, ultrasound, piezoelectric, and thermal sensing technology. 
     The I/O mechanism  1212  may transmit and/or receive data from a user or another electronic device. An I/O device may include a display, a touch sensing input surface such as a track pad, one or more buttons (e.g., a graphical user interface “home” button), one or more cameras, one or more microphones or speakers, one or more ports such as a microphone port, and/or a keyboard. Additionally or alternatively, an I/O device or port may transmit electronic signals via a communications network, such as a wireless and/or wired network connection. Examples of wireless and wired network connections include, but are not limited to, cellular, Wi-Fi, Bluetooth, IR, and Ethernet connections. 
     The foregoing description, for purposes of explanation, uses specific nomenclature to provide a thorough understanding of the described embodiments. However, it will be apparent to one skilled in the art that the specific details are not required in order to practice the described embodiments. Thus, the foregoing descriptions of the specific embodiments described herein are presented for purposes of illustration and description. They are not targeted to be exhaustive or to limit the embodiments to the precise forms disclosed. It will be apparent to one of ordinary skill in the art that many modifications and variations are possible in view of the above teachings.

Metadata:
Filing Date: 20170908
Publication Date: 20191008
Grant Date: 20191008
Priority Date: 20170908
Inventors: LI, XIANGLI
PATEL, Manoj C.
Assignee: APPLE INC
CPC Classifications: [{"code": "H04N25/702", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04N23/672", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04N25/704", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04N25/135", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04N23/67", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04N23/55", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04N23/12", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04N23/672", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04N25/778", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04N23/54", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04N25/704", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04N23/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04N25/75", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04N25/778", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04N23/50", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04N23/12", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04N25/135", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04N2209/042", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02B7/09", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B7/36", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04N9/045", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04N5/378", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B7/09", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04N5/36961", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04N5/3696", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04N5/232122", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B7/36", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L27/1463", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L27/14645", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L27/14621", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04N9/04559", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04N9/07", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04N5/37457", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04N2209/042", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L27/14627", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L27/14641", "inventive": true, "first": false, "tree": "[]"}, {"code": "H10F39/8063", "inventive": true, "first": false, "tree": "[]"}, {"code": "H10F39/8053", "inventive": true, "first": false, "tree": "[]"}, {"code": "H10F39/813", "inventive": true, "first": false, "tree": "[]"}, {"code": "H10F39/807", "inventive": true, "first": false, "tree": "[]"}, {"code": "H10F39/182", "inventive": true, "first": false, "tree": "[]"}, {"code": "H10F39/182", "inventive": true, "first": false, "tree": "[]"}, {"code": "H10F39/813", "inventive": true, "first": false, "tree": "[]"}, {"code": "H10F39/8063", "inventive": true, "first": false, "tree": "[]"}, {"code": "H10F39/807", "inventive": true, "first": false, "tree": "[]"}, {"code": "H10F39/8053", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04N25/75", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04N25/75", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 63528994