CMOS Image Sensors Continue to Advance

With the recent (and deservedly so) hype surrounding motion sensing due to some of the latest mobile phone and gaming creations from Apple, Nintendo, and Sony, it is easy to lose sight of the latest innovations happening in other sensor areas, including CMOS image sensors.

In the consumer electronics market, CMOS image sensor manufacturers are typically tasked with developing components that can deliver higher quality image photos in more mainstream applications. This has been the ongoing mantra for the past several years.

These component suppliers are also meeting the demands of designers who want smaller, ultrathin components that are easier to integrate. Cost is another consideration. (Purchasers are not the only design team partners who are concerned about cost savings!) High definition (HD) video is yet another driver as the consumer’s appetite for the technology keeps growing.

As an example, Aptina recently launched the 3-megapixel (MP) MT9T114 and 5-MP MT9P017 image sensors, leveraging the company’s third-generation Aptina A-Pix technology.

What does Aptina A-Pix technology offer? The company says it makes it possible for mobile phone cameras to capture quality images to compete with digital still cameras and enables a new class of hybrid camera that combines digital still image capture with advanced HD video.

The MT9T113 is one of the first products to integrate the third-generation Aptina A-Pix technology and is said to deliver excellent low-light sensitivity and vibrant colors because of improvements in the technology’s quantum efficiency and reduced crosstalk within the 1.4µm pixel.

What is neat about this sensor is its integrated autofocus (AF) voice coil motor (VCM) driver that makes it the industry’s first 1/5-inch sensor with AF capability. The SoC also provides HD video at 720p/30fps. The MT9P017 device can capture HD video at 1080p/30fps or 720p/30fps.

Earlier this year, OmniVision Technologies launched the OV2720, which is touted as the industry’s first 1/6-inch, native 1080p/30 HD CMOS image sensor designed for notebook, netbook, webcam, and video conference applications.

Of particular importance to notebook designers, the new 1080p sensors, based on OmniVision’s 1.4µm OmniBSI backside illumination technology, delivers video conference quality HD video recording in a small enough form factor to meet the module size and height requirements of thin notebook designs.

The 1.4µm OmniBSI pixel is said to achieve best-in-class low light sensitivity of 680mV/lux-sec, while enabling extremely thin modules with a z-height of 3.5mm. The OV2720 can also use binning to further increase its low-light performance to double that of similar-sized VGA sensors.

In a recent teardown of the Apple iPhone 4, Chipworks suspects that the OmniVision backside illumination (BSI) image sensor (OV5642) found a home on a bill of materials. Not a huge leap of faith since Apple previously announced the sensor uses BSI technology, and OmniVision is one of the very few players with proven BSI technology.

Yole Développement of Lyon, France expects that Aptina Imaging, Samsung, STMicro, and Toshiba will soon offer BSI image sensors as well. Aptina announced its intention to introduce BSI image sensors in the second half of 2010 to address applications requiring 1.1µm pixels and below.

Toshiba’s latest addition to its Dynastron® portfolio, which was introduced in October of last year, is also the company’s first to integrate the enhanced sensitivity offered by BSI. Mass production is expected in the third quarter of 2010.

You can also find image sensors in applications beyond consumer electronics, including instrumentation, medical equipment, and automotive applications. Developments in these non-consumer applications are bringing about some significant breakthroughs.

Case in point: Cypress Semiconductor recently unveiled its 25-megapixel VITA 25K image sensors that are said to offer the industry’s highest throughput for a device with a pipelined and triggered global shutter. Aimed at high-end machine vision applications, the sensor provides 32 10-bit digital low voltage differential signaling (LVDS) outputs that enable transfer of image data over a standard industry protocol at low power and low noise. Each channel runs at 620Mbits/s, which results in a high frame rate of 53 frames-per-second (fps) at full resolution, delivering undistorted images and fast readout, said Cypress.

Sensor manufacturers are doing more than developing new products. Some are beefing up their development tools to help designers configure their sensor products.

Toshiba America Electronic Components, Inc., for example, recently partnered with Imatest, a maker of image quality testing software, to enhance Imatest’s Image Sensor (IS) Edition, a tool designed to help engineers configure image sensors.

Toshiba says the process of correctly configuring image sensors involves a number of steps that include setting sensor registers, capturing images, conducting tests, and analyzing results, which is repeated to achieve an ideal configuration for each application and each sensor.

The IS Edition interfaces with image sensor configuration software, allowing images to be directly read from the sensor and analyzed, providing product engineers with the information they need to optimize their sensor settings, said Toshiba. These include sharpness, noise, blemish detection, dynamic range, color accuracy, distortion, uniformity, lateral chromatic aberration, veiling glare, ISO sensitivity, and color moiré.

The IS Edition also interfaces with image sensors from Aptina and OmniVision.