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(12) United States Patent (10) Patent No.: US 9,712,792 B2 Shi Et Al

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(12) United States Patent (10) Patent No.: US 9,712,792 B2 Shi Et Al USO097 12792B2 (12) United States Patent (10) Patent No.: US 9,712,792 B2 Shi et al. (45) Date of Patent: Jul.18, 2017 (54) RGB-RWB DUAL MAGES BY (56) References Cited MULTI-LAYER SENSORS TOWARDS BETTER IMAGE QUALITY U.S. PATENT DOCUMENTS Applicants: Lilong Shi, Pasadena, CA (US); Ilia 7,129,466 B2 * 10/2006 Iwasaki ................. HOL27/302 (71) 250,208.1 Ovsiannikov, Studio City, CA (US) 8,314,863 B2 11/2012 Tachi (72) Inventors: Lilong Shi, Pasadena, CA (US); Ilia (Continued) Ovsiannikov, Studio City, CA (US) OTHER PUBLICATIONS (73) Assignee: SAMSUNG ELECTRONICS CO., LTD. (KR) Ihama, Mikio, et al., “Proposal of New Organic CMOS Image Sensor for Reduction in Pixel Size.” Fujifilm Research & Devel (*) Notice: Subject to any disclaimer, the term of this opment (No. 55-2010), pp. 14-17. patent is extended or adjusted under 35 U.S.C. 154(b) by 0 days. (Continued) Primary Examiner — Padma Haliyur (21) Appl. No.: 14/924,704 (74) Attorney, Agent, or Firm — Renaissance IP Law (22) Filed: Oct. 27, 2015 Group LLP (65) Prior Publication Data (57) ABSTRACT US 2017/OO485OO A1 Feb. 16, 2017 Using improved Image Signal Processing (ISP) along with a multi-layer Color Filter Array (CFA) architecture to cap Related U.S. Application Data ture both the Red-Green-Blue (RGB) as well as the Red-X- (60) Provisional application No. 62/203,390, filed on Aug. Blue (RXB) images substantially simultaneously on the 10, 2015. same Complementary Metal Oxide Semiconductor (CMOS) image sensor chip in a single shot so that Subsequent image (51) Int. Cl. processing stage(s) can choose between RGB and RXB H04N 9/04 (2006.01) images to improve the quality of the final image. The color H04N 5/225 (2006.01) “X” in the RXB image may be a white color, a yellow color, H04N 9/64 (2006.01) or a cyan color. In contrast to the individual RWB or RGB (52) U.S. C. imaging based conventional CMOS sensors, the disclosed CPC ............. H04N 9/045 (2013.01); H04N 9/646 CMOS sensor with one or more layers of specifically (2013.01); H04N 2209/045 (2013.01); H04N selected CFAs can capture both the RGB and RXB images 2209/046 (2013.01); H04N 2209/047 in a single shot using associated ISP. The multi-layer sensor (2013.01) may be an organic sensor or a stacked X3 sensor. The dual (58) Field of Classification Search RGB-RXB imaging may reduce colorblindness, chromatic CPC ...... H04N 9/045; H04N 9/646; H04N 5/2254; aberration, and Saturation artifacts. HO4N 5/2253 See application file for complete search history. 20 Claims, 8 Drawing Sheets Multi-Layer Image Sensor Unit CFA Layer (on top) 33 CFA Layer-2 (at bottom) Pixel Array Control and Processing Circuits Pixel Electrodest Photo-Sites US 9,712,792 B2 Page 2 (56) References Cited U.S. PATENT DOCUMENTS 2013,0242148 A1 9, 2013 Mlinar et al. 2015, 0116545 A1 4/2015 Ovsiannikov et al. OTHER PUBLICATIONS Lim, Seon-Jeong et al., “Organic-on-silicon complementary metal oxide-semiconductor colour image sensors,” Scientific Reports, www.nature.com/scientificreports, 5:7708 DOI: 10.1038/ Srep07708, published Jan. 12, 2015, pp. 1-7. * cited by examiner U.S. Patent Jul.18, 2017 Sheet 1 of 8 US 9,712,792 B2 FIG. 1 Processor Multi-Layer Image Sensor Unit O Multi-Layer Image Sensor Unit CFA Layer-1 12 CFA Layer-2 (at bottom) Pixel Array Control and Processing Circuits Pixel Electrodes/ Photo-Sites U.S. Patent Jul.18, 2017 Sheet 2 of 8 US 9,712,792 B2 pixel signals RGB array RWB array 18 Pixel Hardware 20 42 46 ISP (software) 48 FIG. 3 Provide a multi-layer image sensor having a plurality of pixels arranged in a pixel array and further having at least one layer of CFA overlaid on the pixel array such that at least one location-specific color filter is associated with each pixel location in the pixel array. Collect one or more color signals from each pixel location in the pixel array during a single imaging Operation. Each Color signal associated with a given pixel location represents a different color of light. Selectively combine color signals from each pixel location to construct the following two color patterns; each Color pattern has Colors arranged in one-to-one Correspondence with each pixel location in the pixel array: (1) an RGB color pattern, and (2) an RXB color pattern, wherein "X" represents one of the following colors: white, yellow, or cyan. 50 FIG. 4 U.S. Patent Jul.18, 2017 Sheet 3 of 8 US 9,712,792 B2 9'OIH o 99 o 99 U.S. Patent Jul.18, 2017 Sheet 4 of 8 US 9,712,792 B2 & > N O ) O 25 O 3 a 3 t 3 ON oooo a rt l oooo oooo >St aga CD Cao y r s l 9 O) \d = r C s 9 C E o (d R 9E is O ?h CO is a o os Y 7. A so e o odC 1 << CD N <ogo s << da) N HIH - CD Y & P 2 Cawere won an o a s bOSSP as , s As a 2 2. C C. s 8 3 St is á Y. - Ow E Ed CD s - is O U.S. Patent Jul.18, 2017 Sheet S of 8 US 9,712,792 B2 a 3. 2. 32is 9 S 2 53. C 33 ca 53 II I É I I IoHo I IoHo s C C C w CD o s s d w U.S. Patent Jul.18, 2017 Sheet 6 of 8 US 9,712,792 B2 86 WOO pºlonInsuoC) Ke-IIeROYI U.S. Patent Jul.18, 2017 Sheet 7 of 8 US 9,712,792 B2 100 A A 102 EAEA AHA FIG 10 m A to A CFA Layer-1 CFA Layer-2 (MYC organic layer) (RGB non-organic layer) Green o F Blue E = Yellow = Red A = Magenta F Cyan 116 Foveon X3 sensor Stack Blue filter 118 ? Redfilter 120 K- a 7 microns -> 108 no filter II Green SensOr Green Sensor Green SensOr Green SensOr 107 Red Sensor Red Sensor Red Sensor Red Sensor 106 113 FIG. 11A 104 12 FIG. 11B Nilo CFA1222, Layer o aso a U.S. Patent Jul.18, 2017 Sheet 8 of 8 US 9,712,792 B2 SYSTEM 135 Power Supply Unit image sensor PROCESSOR Display Unit 13 Peripheral NetWork Storage Interface FIG. 13 US 9,712,792 B2 1. 2 RGB-RWB DUAL MAGES BY when the image is converted to the standard color space by MULTI-LAYER SENSORS TOWARDS the CCM of the RWB sensor, the noise will not be amplified BETTER IMAGE QUALITY as much. As a result, the final image by the RWB sensor has less noise than that by the comparable RGB sensor. CROSS-REFERENCE TO RELATED Moreover, current RWB sensors may suffer from color APPLICATIONS blindness and chromatic aberration artifacts. Colorblindness arises because an RWB sensor can be “blind' to certain color This application claims the priority benefit under 35 edges which an RGB sensor has no problem distinguishing. U.S.C. S 119(e) of U.S. Provisional Application No. 62/203, On the other hand, chromatic aberration arises because red, 390 filed on Aug. 10, 2015, the disclosure of which is 10 green, and blue lights have different diffraction ratios and, incorporated herein by reference in its entirety. hence, they may focus in front of back to the image plane, or at different locations even if they all focus on the image TECHNICAL FIELD plane. Chromatic aberration may be present, especially in the absence of a Sophisticatedly-designed lens to completely The present disclosure generally relates to image sensors. 15 eliminate such aberration. When chromatic aberration More specifically, and not by way of limitation, particular occurs, the white light signal—containing the red, green, embodiments of the inventive aspects disclosed in the pres and blue components—will be blurry because of the mixing ent disclosure are directed to a multi-layer Complementary of lights at different focus points. On the other hand, the Metal Oxide Semiconductor (CMOS) image sensor where traditional RGB sensor has lower chromatic aberration than Red-Green-Blue (RGB) and Red-White-Blue (RWB) the RWB sensor. images having Bayer patterns are generated on the same chip Substantially simultaneously during a single shot to SUMMARY allow choice of RGB or RWB image during subsequent image processing operations such as, for example, color In one embodiment, the present disclosure is directed to correction, noise reduction, reduction of chromatic aberra 25 a method that comprises: (i) providing a multi-layer image tion, and reduction of colorblindness. sensor having a plurality of pixels arranged in a pixel array and further having at least one layer of Color Filer Array BACKGROUND (CFA) overlaid on the pixel array such that at least one location-specific color filter is associated with each pixel In commercial mobile products Such as, for example, cell 30 location in the pixel array; (ii) collecting one or more color phones, CMOS RWB imaging sensor has been recently signals from each pixel location in the pixel array during a introduced as the image sensor for the cell phone's camera. Single imaging operation, wherein each color signal associ The RWB sensor includes a Color Filter Array (CFA) of red, ated with a given pixel location represents a different color white, and blue color filters arranged in a Bayer color of light; and (iii) selectively combining color signals from pattern.
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