Imaging systems having image sensor pixel arrays with phase detection capabilities

• US 9,749,556 B2
• Filed: 03/24/2015
• Issued: 08/29/2017
• Est. Priority Date: 03/24/2015
• Status: Active Grant

• Current Assignee: Semiconductor Components Industries LLC (ON Semiconductor Corporation)
• Original Assignee: Semiconductor Components Industries LLC (ON Semiconductor Corporation)
• Inventors: Fettig, Douglas, Mlinar, Marko, Gravelle, Jr., Robert M.
• Primary Examiner(s): Haskins, Twyler
• Assistant Examiner(s): Quiett, Carramah J
• Application Number:
  US14/667,286
• Publication Number:
  US 20160286108A1
• Time in Patent Office: 889 Days
• CPC Class Codes: G06T 2207/10024 Color image
• CPC Class Codes: G06T 2207/20012 Locally adaptive
• CPC Class Codes: G06T 2207/20208 High dynamic range [HDR] image processing
• CPC Class Codes: G06T 3/4015 Image demosaicing, e.g. colour filter arrays [CFA] or Bayer patterns
• CPC Class Codes: G06T 5/20 using local operators
• CPC Class Codes: G06T 5/70 Denoising; Smoothing
• CPC Class Codes: G06T 5/94 based on local image properties, e.g. for local contrast enhancement
• CPC Class Codes: H01L 27/14627 Microlenses
• CPC Class Codes: H01L 27/14641 Electronic components shared by two or more pixel-elements, e.g. one amplifier shared by two pixel elements
• CPC Class Codes: H01L 27/14643 Photodiode arrays; MOS imagers
• CPC Class Codes: H04N 2209/046 Colour interpolation to calculate the missing colour values
• CPC Class Codes: H04N 23/667 Camera operation mode switching, e.g. between still and video, sport and normal or high- and low-resolution modes
• CPC Class Codes: H04N 23/672 based on the phase difference signals
• CPC Class Codes: H04N 23/73 by influencing the exposure time
• CPC Class Codes: H04N 23/741 by increasing the dynamic range of the image compared to the dynamic range of the electronic image sensors
• CPC Class Codes: H04N 25/134 based on three different wavelength filter elements
• CPC Class Codes: H04N 25/46 by combining or binning pixels
• CPC Class Codes: H04N 25/583 with different integration times
• CPC Class Codes: H04N 25/704 Pixels specially adapted for focusing, e.g. phase difference pixel sets

Abstract

An image sensor may have a pixel array that includes an array of pixels arranged in rows and columns. Each pixel may include a number of adjacent sub-pixels covered by a single microlens. The adjacent sub-pixels of each pixel may include color filter elements of the same color. Image signals from the sub-pixels may be used to calculate phase information in each pixel in the array. This information may be used to generate a depth map of the entire captured image. The pixels may each be able to detect vertical, horizontal, or diagonal edges. Additionally, the image signals from each photodiode in a pixel may be binned or average to obtain image data for each pixel. The image sensor also may generate high-dynamic-range images using the pixel array.

Claims

1. A method of operating an imaging system having an array of pixels arranged in rows and columns, wherein each pixel comprises four adjacent photosensitive areas located in two adjacent columns and two adjacent rows, and wherein each pixel comprises a microlens that covers the four adjacent photosensitive areas, the method comprising:

generating image signals in the four adjacent photosensitive areas of each pixel;

processing the image signals of each of the four adjacent photosensitive areas of a first pixel of the array of pixels to determine phase information, wherein only the image signals of each of the four adjacent photosensitive areas of the first pixel are used to determine the phase information, wherein processing the image signals of each of the four adjacent photosensitive areas of the first pixel to determine phase information comprises processing the image signals of each of the four adjacent photosensitive areas of the first pixel to detect vertical edges, horizontal edges, and diagonal edges, and wherein only the image signals of each of the four adjacent photosensitive areas of the first pixel are used to detect the vertical edges, horizontal edges, and diagonal edges; and

processing the image signals of each of the four adjacent photosensitive areas of the first pixel to determine image information, wherein only the image signals of each of the four adjacent photosensitive areas of the first pixel are used to determine the image information, and wherein processing the image signals of each of the four adjacent photosensitive areas of the first pixel to determine the image information comprises averaging the image signals of each of the four adjacent photosensitive areas to obtain a single image signal value for the first pixel.

2. The method defined in claim 1, wherein each pixel comprises a color filter element that covers the four adjacent photosensitive areas.

3. The method defined in claim 2, wherein the color filter element of each pixel is part of a Bayer color pattern.

4. The method defined in claim 1, wherein processing the image signals of each of the four adjacent photosensitive areas of the first pixel to determine phase information comprises processing the image signals to detect at least one of red edges and blue edges.

5. A method of operating an imaging system having an array of pixels arranged in rows and columns, wherein each pixel comprises four adjacent photosensitive areas located in two adjacent columns and two adjacent rows, and wherein each pixel comprises a microlens that covers the four adjacent photosensitive areas, the method comprising:

generating image signals in the four adjacent photosensitive areas of each pixel;

processing the image signals of each of the four adjacent photosensitive areas of at least one pixel to determine phase information, wherein processing the image signals of each of the four adjacent photosensitive areas of the at least one pixel to determine phase information comprises processing the image signals of each of the four adjacent photosensitive areas of the at least one pixel to detect vertical edges, horizontal edges, and diagonal edges, and wherein only the image signals of each of the four adjacent photosensitive areas of the at least one pixel are used to detect the vertical edges, horizontal edges, and diagonal edges; and

processing the image signals of each of the four adjacent photosensitive areas of the at least one pixel to determine image information wherein the four adjacent photosensitive areas include first, second, third, and fourth photosensitive areas, wherein the first photosensitive area in a plurality of the pixels has a first integration time, wherein the second photosensitive area in the plurality of the pixels has a second integration time, and wherein the first integration time is longer than the second integration time.

6. The method defined in claim 5, wherein the first photosensitive area is positioned diagonally opposite the second photosensitive area.

7. The method defined in claim 5, wherein the first photosensitive area is positioned in the same row as the second photosensitive area.

8. The method defined in claim 5, further comprising generating a high dynamic range image using the image signals from the plurality of the pixels.