Sony Develops New Back-Illuminated CMOS Image Sensors For Smartphones
Sony has developed a new series of back-illuminated
CMOS image sensosr for mobile devices, promising to
offer enhanced image quality and superior
functionalities at a more compact size.
Conventional CMOS image sensors mount the pixel
section and analog logic circuit on top of the same
chip, which require numerous constraints when wishing
to mount the large-scale circuits such as measures to
counter the circuit scale and chip size, measures to
suppress noise caused by the layout of the pixel and
circuit sections, and optimizing the characteristics
of pixels and circuit transistors.
Sony has established a structure that layers the pixel section containing formations of back-illuminated structure pixels over the chip affixed with mounted circuits for signal processing, which is in place of supporting substrates used for conventional back-illuminated CMOS image sensors. With this stacked structure, large-scale circuits can now be mounted keeping small chip size. Furthermore, as the pixel section and circuit section are formed as independent chips, a manufacturing process can be adopted, enabling the pixel section to be specialized for higher image quality while the circuit section can be specialized for higher functionality, thus simultaneously achieving higher image quality, superior functionality and a more compact size. In addition, faster signal processing and lower power consumption can also be achieved through the use of leading process for the chip containing the circuits.
As the first step towards the commercialization of its new CMOS image sensors, Sony has developed a model with built-in signal processing functionality, an element that usually requires external embedment. Samples will be shipped from March, 2012.
The new CMOS models have been also developed with Sony's "RGBW Coding" function, which contributes to low noise, high quality image capturing even in low light condition, and the proprietary "HDR (High Dynamic Range) Movie" function, which achieves brilliant color even when taking pictures against bright light.
The built-in "RGBW Coding" function adds W (White) pixels to the conventional range of RGB (Red-Green-Blue) pixels, realizing higher sensitivity and enabling high-quality shooting with low noise even in dark indoor or night settings. While the addition of W (White) pixels improves sensitivity, the image quality typically degrades. Sony claims that its own device technology and signal processing realizes superior sensitivity without hurting image quality. Furthermore, while the individual pixels of the newly developed models are extremely minute at 1.12um, the incorporation of the "RBGW Coding" function has realized a SN ratio (signal-to-noise ratio) equivalent to that of a unit pixel size of 1.4um under conventional methods, which in turn enable the image sensors to achieve a higher resolution at a more compact size.
The new models are also able to output signals through the conventional RGB method, thus there is no need to change the signal processing adopted in existing devices.
Typically, when shooting with differing light levels, such as an indoor setting against a bright outdoor background, there can easily be blocked up shadows for dark areas or blown out highlights for bright areas. Such phenomena are a result of the combination of low-light and bright-light which have different optimal exposure conditions in the same shot. Sony's HDR (High Dynamic Range) Movie function reduces this by setting two different exposure conditions within a single screen shooting and conducts the appropriate signal processing for the captured image information under each optimal exposure condition. This process generates an image with a broad dynamic range and enables shooting of both the background and subject matter with brilliant colors even in a bright environment.
Sony plans to develop the fllowing CMOS image sensor models within 2012:
- Type 1/4 Stacked CMOS Image Sensor with approx. 8.0 effective megapixels (equipped with camera signal processing function) - Sample shipments planned for March, 2012
- Type 1/3.06 Stacked CMOS Image Sensor with approx. 13.0 effective megapixels (equipped with "RGBW Coding" and "HDR Movie" functions) - Sample shipments planned for June, 2012
- Type 1/4 Stacked CMOS Image Sensor with approx. 8.0 effective megapixels (equipped with "RGBW Coding" and "HDR Movie" functions) - Sample shipments planned for August, 2012
Sony has established a structure that layers the pixel section containing formations of back-illuminated structure pixels over the chip affixed with mounted circuits for signal processing, which is in place of supporting substrates used for conventional back-illuminated CMOS image sensors. With this stacked structure, large-scale circuits can now be mounted keeping small chip size. Furthermore, as the pixel section and circuit section are formed as independent chips, a manufacturing process can be adopted, enabling the pixel section to be specialized for higher image quality while the circuit section can be specialized for higher functionality, thus simultaneously achieving higher image quality, superior functionality and a more compact size. In addition, faster signal processing and lower power consumption can also be achieved through the use of leading process for the chip containing the circuits.
As the first step towards the commercialization of its new CMOS image sensors, Sony has developed a model with built-in signal processing functionality, an element that usually requires external embedment. Samples will be shipped from March, 2012.
The new CMOS models have been also developed with Sony's "RGBW Coding" function, which contributes to low noise, high quality image capturing even in low light condition, and the proprietary "HDR (High Dynamic Range) Movie" function, which achieves brilliant color even when taking pictures against bright light.
The built-in "RGBW Coding" function adds W (White) pixels to the conventional range of RGB (Red-Green-Blue) pixels, realizing higher sensitivity and enabling high-quality shooting with low noise even in dark indoor or night settings. While the addition of W (White) pixels improves sensitivity, the image quality typically degrades. Sony claims that its own device technology and signal processing realizes superior sensitivity without hurting image quality. Furthermore, while the individual pixels of the newly developed models are extremely minute at 1.12um, the incorporation of the "RBGW Coding" function has realized a SN ratio (signal-to-noise ratio) equivalent to that of a unit pixel size of 1.4um under conventional methods, which in turn enable the image sensors to achieve a higher resolution at a more compact size.
The new models are also able to output signals through the conventional RGB method, thus there is no need to change the signal processing adopted in existing devices.
Typically, when shooting with differing light levels, such as an indoor setting against a bright outdoor background, there can easily be blocked up shadows for dark areas or blown out highlights for bright areas. Such phenomena are a result of the combination of low-light and bright-light which have different optimal exposure conditions in the same shot. Sony's HDR (High Dynamic Range) Movie function reduces this by setting two different exposure conditions within a single screen shooting and conducts the appropriate signal processing for the captured image information under each optimal exposure condition. This process generates an image with a broad dynamic range and enables shooting of both the background and subject matter with brilliant colors even in a bright environment.
Sony plans to develop the fllowing CMOS image sensor models within 2012:
- Type 1/4 Stacked CMOS Image Sensor with approx. 8.0 effective megapixels (equipped with camera signal processing function) - Sample shipments planned for March, 2012
- Type 1/3.06 Stacked CMOS Image Sensor with approx. 13.0 effective megapixels (equipped with "RGBW Coding" and "HDR Movie" functions) - Sample shipments planned for June, 2012
- Type 1/4 Stacked CMOS Image Sensor with approx. 8.0 effective megapixels (equipped with "RGBW Coding" and "HDR Movie" functions) - Sample shipments planned for August, 2012
