Sony to Debut 'Stacked' CMOS Image Sensor
Sony Corp will release what it claims is the industry's first back-illuminated CMOS image sensor that uses a "stacked structure."
The announcement was made Aug 20, 2012. Sony will release three models of the CMOS sensor, "Exmor RS." And they have higher sensitivities and wider dynamic ranges than the company's existing products. Also, Sony will start to ship three modules equipped with those sensors in October 2012.
Sony expects that the new CMOS sensor will be used for mobile devices such as smartphones and tablet computers and employed for smartphones to be launched at the end of 2012. In the image sensor market, in which about 1.5 billion units were shipped in fiscal 2011, the company aims to ship 100 million units of the new sensor per year, said Yasuhiro Ueda, senior general manager, Image Sensor Business Division, Semiconductor Business Group, Professional, Device & Solutions Group, SVP, Corporate Executive, Sony.
The Exmor RS back-illuminated CMOS sensor has a structure in which the sensor (image pickup device) part and the logic circuit part, which is for signal processing, are separated and three-dimensionally stacked. For the 3D stacking, a technique similar to TSV (through silicon via) is used, Ueda said.
The structure not only contributed to the small size and high image quality of the CMOS sensor but enabled to embed various functions (that were externally attached to devices in the past) in the logic circuit part of the CMOS sensor. Sony explained this concept at a press conference that it organized in January 2012.
The three models to be launched by Sony are the 1/3.06-inch "IMX135" with a pixel count of 13.13 million, the 1/4-inch "IMX134" with a pixel count of 8.08 million and the 1/4-inch "ISX014" with a pixel count of 8.08 million. The pixel pitch of the three models is 1.12μm, which the company claims is the smallest in the industry.
The IMX135 and IMX134 have the "RGBW coding function" and "HDR (high dynamic range) movie function" in their logic circuit parts.
(Continue to the next page)
The RGBW coding function improves sensitivity by adding white pixels to RGB (red, green and blue) pixels so that clear images can be taken even in a dark room or during nighttime hours. The HDR movie function sets two kinds of exposure conditions inside pixels at the time of shooting a movie and applies signal processing to the images taken under the conditions so that pixels with a wide dynamic range are created.
The ISX014 comes with an image quality adjustment function and other functions that process camera signals.
Sony plans to ship samples of the IMX135, IMX134 and ISX014 in January 2013, March 2013 and October 2012, respectively, at prices of ¥1,500 (approx US$18.89), 1,000 and 1,200 (including tax).
Furthermore, Sony will release three modules, each of which is equipped with one of the three models of the new CMOS sensor and a lens unit having an autofocus mechanism. The "IU135F3-Z," "IU134F9-Z" and "IUS014F-Z" modules come with the IMX135, IMX134 and ISX014, respectively.
The IU135F3-Z has a high-resolution lens whose F value is 2.2. The IU134F9-Z, which measures 8.5 x 8.5 x 4.2mm, features a volume 14% less than Sony's existing product. The IUS014F-Z comes with embedded autofocus and image quality adjustment functions.
The shipments of the IU135F3-Z, IU134F9-Z and IUS014F-Z will begin in March 2013, May 2013 and November 2012, respectively, with sample prices of ¥8,000, 5,000 and 6,000 (including tax).
At the press conference that took place Aug 20, 2012, Tomoyuki Suzuki, Sony's corporate executive officer and EVP, president of Device Solutions Business Group, president of Core Device Development Group, who supervises the company's device business took the podium.
"Image sensors play an important role in Sony's core business," he said. "Our CMOS sensors have almost reached a point where they are superior to human eyes. And we will pursue further advances. We will be engaged in the image sensor business with a resolution to change Sony with devices."