Friday, August 27, 2010

Omnivision Q1F2011 earnings call

Via seeking alpha. some choice quotes:

First, let me share with you our commitment with BSI technologies development. Our commitment to the advancement of BSI technologies is second to none. As the first company to commercialize the use of this technology, our first generation OmniBSI pixel is already in mass production and has begun to ramp significantly in fiscal 2011 and serves as the basic for our entire 5-megapixel product line.

With the advancement of BSI-2, the second generation OmniBSI pixel, we have further expanded our leadership in pixel technology well ahead of our competitors. The second generation BSI architecture represents a major milestone in digital imaging technology in an aggressive form factor. Meanwhile, most significantly, these technologies serve the basic for meeting the trend towards ever higher pixel counts and establish a trend towards high quality pixel.

Another notable commitment enduring in core sensing technology is our CameraCube technology development. In particular, we remain focused on the development of advanced wafer level optics and packaging solutions for our next generation products and reduce product costs. To this end, we are consistently examining our options and look for solutions to achieve our goal.

Last, but not least, through fiscal 2010, our OmniPixel3-HS technologies continued to gain traction with broad market acceptance due to its leading low light sensitivity. Our latest high performance VGA sensor that is built with our popular 3.0 micron OmniPixel3-HS high sensitivity pixel is well accepted in automotive and the security markets, which also demand high definition color applications.


Currently, a major trend and expectation in imaging is the increasingly rapid marketplace adoption of high sensitivity, high definition images and video.


Our BSI products are proven to be a key differentiator that has enabled OmniVision to secure a range of high value customers and projects. We expect that our proprietary BSI technology will continue to be a decisive factor in securing further design wins during the next several quarters resulting in an increasingly prominent position within our vertical target markets.


In regards to technology of BSI, obviously to ship the quantities that we are shipping today, it’s a long learning curve. We regard that as extremely a big advantage to OmniVision, and our competitors will probably face that step when they get to it. And it’s not easy to ship the volumes we have.


We have been developing the backside illumination technology with our strategic partner TSMC for many years. This has been a five-year effort for us. And there has been a tremendous amount of intellectual property developed between the two companies in that process. And that’s very hard to reproduce and is very hard to reproduce in a short time period. So if you look at our success and the growth we’ve seen, it’s really been fueled by BSI. So that should give you an indication that a great portion of that learning has already taken place for us. So we think that as a big barrier for the competition.

Thursday, August 26, 2010

Pixel ADC MSc Thesis online

Oops, Image Sensors World beat me to the scoop, and I've been the daily supervisor at imec :-)

Cheng Ma's MSc thesis is available: "Pixel ADC Design for Hybrid CMOS Image Sensor". Good luck in your new job in Antwerp!

Friday, August 20, 2010

Paper watch: Image sensor papers at the IEEE TED

The latest issue of IEEE Transactions on Electron Devices carries three (at first sight) interesting papers.

The first one is "eLeNA: A Parametric CMOS Active-Pixel Sensor for the Evaluation of Reset Noise Reduction Architectures". The abstract reads:
We present a novel complementary metal–oxide–semiconductor (CMOS) active-pixel sensor imager that incorporates different reset schemes to achieve lower reset noise levels. The sensor, eLeNA, features a 448 $times$ 512 array with a pixel pitch of 15 $muhbox{m}$, fabricated using a 0.18- $muhbox{m}$ CMOS process. Fourteen sections and five different reset methods were employed. Without using pinned diodes, we implanted structures for correlated double sampling. A noise of 6 $hbox{e}-$ is measured with a conversion gain of 49 $muhbox{V/e}-$. We will discuss various applications for the reset method that achieved the best overall performance, considering leakage current and read noise.
The second one is: "Simulation and Measurements of Stray Minority Carrier Protection Structures in CMOS Image Sensors". The abstract reads:
Recently, the rapid growth of CMOS technology has made it possible to integrate more periphery circuits into a CMOS image sensor. Although these periphery circuits improve image quality, they also lead to the generation of more stray minority carriers. Because the number of stray minority carriers is proportional to the frequency, the affected region increases with increasing operating frequency. Placing an appropriate absorber between the periphery circuits and the pixel has traditionally been accepted as the best solution for this issue. Four protection tactics were simulated in software and verified in a fabricated CMOS image sensor. The imager was fabricated using TSMC 1-poly 6-metal 0.18-$muhbox{m}$ process technology. On this chip, ten noise sources outside the pixel array were used to verify the effectiveness of the protection tactics in off-array tests, whereas in-pixel noise sources were used in in-pixel tests. To quantify the influence of stray minority carriers in the off-array test, the maximum depth of an affected region (DAR) was measured in a processed binary image. The off-array experimental results revealed that the DAR increased with either an increased operating frequency or a decreased separation between the noise source and the pixel array. The DAR of the affected pixels can be eliminated up to 48.1% and 23.8% by using the N-well and N-diffusion guard rings, respectively. The in-pixel experimental results have shown that the N-diffusion digital pixel implementation reduced the noise by 63.2% while only increasing the area by 10.68%. Detailed information about the effectiveness of different protection tactics in an imager design was collected in this paper. This paper can potentially provide a reference to help imager designers choose an appropriate protection tactic.
And the third one: "Per-Pixel Dark Current Spectroscopy Measurement and Analysis in CMOS Image Sensors". The abstract reads:
A per-pixel dark current spectroscopy measurement and analysis technique for identifying deep-level traps in CMOS imagers is presented. The short integration time transfer gate subtraction experimental technique used to obtain accurate results is described and discussed. The activation energies obtained for molybdenum (≈0.3 eV), tungsten (≈0.37 eV), and the phosphorus-vacancy (E-center) (≈0.44 eV) trap levels in silicon match published results measured with other techniques. The Meyer–Neldel Relationship (MNR) was observed between the Arrhenius preexponential frequency factor and activation energy. The trap capture cross-sectional calculation methodology using the MNR is presented. The cross sections of molybdenum, tungsten, and the E-center were calculated as ≈1 × 10−16 cm2,
≈1.5 × 10−16 cm2, and≈2.5 × 10−16 cm2, respectively, at 318 K. The data obtained suggest electric field enhanced emission, and Poole-Frenkel barrier force lowering of E-center defects occurs in the pinning implant regions. It is proposed that a changing Fermi level results in the correct activation energies being obtained below half the band gap and that the dark current measurement process is affected by the measurement time result of statistical mechanics. It is also tentatively suggested that, in this case, the observed MNR is a geometric relationship and not due to a physical process.
In case the abstract is a bit confusing, the authors conclude that: "The measurement and analysis technique presented could be useful to the image sensor industry for diagnosing fabrication plant contamination. It also has potential applications for the study of radiation induced traps in CMOS and CCD imagers."

Thursday, August 19, 2010

Paper watch: Another step towards usable organic photodiodes

New paper at Applied Physics Letters: "Organic heterojunction photodiodes exhibiting low voltage, imaging-speed photocurrent gain". The abstract reads:
We report the demonstration of fast and strong photocurrent gain in organic photodiodes with tailored charge blocking layers. The hole blocking layer between the anode and the photoactive layer leads to accumulation of photogenerated holes at its interface with the active layer, which causes a strong secondary electron injection from the anode and as such a high photocurrent gain. Using a bulk heterojunction of C60 and copper phthalocyanine as the active layer, we have achieved photocurrent gains up to 500 across the visible spectrum and bandwidths on the order of 1 kHz, well above the imaging-compatible bandwidth (>60 Hz).

TOF camera projects in Europe

An FP6 project for short range 3D imaging: ARTTS. Article at CORDIS.

An FP7 project for SPAD-based 3D imaging: MISPIA (could not find a project website).

Tuesday, August 17, 2010

Paper watch: Latest IEEEXplore update

Plenty of noteworthy papers in today's IEEEXplore .These are some which will be on my to-read list, based on the abstracts.

First, from TCAS-II:"Event-Driven Data Acquisition and Digital Signal Processing—A Tutorial" from Yannis Tsividis. The abstract reads:
"Event-driven analog-to-digital conversion and associated digital signal processing techniques are reviewed. Such techniques, still in the research stage, have the potential to significantly reduce the consumption of energy and bandwidth resources in several important applications."

From IEEE's Transactions on Image Processing, a paper from Sony's Image Sensing Technology Department: "Generalized Assorted Pixel Camera: Postcapture Control of Resolution, Dynamic Range, and Spectrum". The abstract reads:
We propose the concept of a generalized assorted pixel (GAP) camera, which enables the user to capture a single image of a scene and, after the fact, control the tradeoff between spatial resolution, dynamic range and spectral detail. The GAP camera uses a complex array (or mosaic) of color filters. A major problem with using such an array is that the captured image is severely under-sampled for at least some of the filter types. This leads to reconstructed images with strong aliasing. We make four contributions in this paper: 1) we present a comprehensive optimization method to arrive at the spatial and spectral layout of the color filter array of a GAP camera. 2) We develop a novel algorithm for reconstructing the under-sampled channels of the image while minimizing aliasing artifacts. 3) We demonstrate how the user can capture a single image and then control the tradeoff of spatial resolution to generate a variety of images, including monochrome, high dynamic range (HDR) monochrome, RGB, HDR RGB, and multispectral images. 4) Finally, the performance of our GAP camera has been verified using extensive simulations that use multispectral images of real world scenes. A large database of these multispectral images has been made available at for use by the research community.
The latest Transactions on Nuclear Science serves as proceedings from the RADECS 2009 conference. Some choice papers:
From the conventional TNS issue:

Saturday, August 14, 2010

A "copernican shift" in science?

First it was discovering the LiquidPub project:
The LiquidPub project proposes a paradigm shift in the way scientific knowledge is created, disseminated, evaluated and maintained. This shift is enabled by the notion of Liquid Publications, which are evolutionary, collaborative, and composable scientific contributions. Many Liquid Publication concepts are based on a parallel between scientific knowledge artifacts and software artifacts, and hence on lessons learned in (agile, collaborative, open source) software development, as well as on lessons learned from Web 2.0 in terms of collaborative evaluation of knowledge artifacts.
And then I read this article about how sharing scientific data has led to advances in the fight against Alzheimer's.

At first, the collaboration struck many scientists as worrisome — they would be giving up ownership of data, and anyone could use it, publish papers, maybe even misinterpret it and publish information that was wrong.

But Alzheimer’s researchers and drug companies realized they had little choice.

Thursday, August 5, 2010

Paper watch: A cheap portable fluorescence microscope

Via Nanowerk, a new paper at PLoS: "Portable, Battery-Operated, Low-Cost, Bright Field and Fluorescence Microscope". The abstract reads:
This study describes the design and evaluation of a portable bright-field and fluorescence microscope that can be manufactured for $240 USD. The microscope uses a battery-operated LED-based flashlight as the light source and achieves a resolution of 0.8 ┬Ám at 1000× magnification in fluorescence mode. We tested the diagnostic capability of this new instrument to identify infections caused by the human pathogen, Mycobacterium tuberculosis. Sixty-four direct, decontaminated, and serially diluted smears were prepared from sputa obtained from 19 patients suspected to have M. tuberculosis infection. Slides were stained with auramine orange and evaluated as being positive or negative for M. tuberculosis with both the new portable fluorescence microscope and a laboratory grade fluorescence microscope. Concordant results were obtained in 98.4% of cases. This highly portable, low cost, fluorescence microscope may be a useful diagnostic tool to expand the availability of M. tuberculosis testing at the point-of-care in low resource settings.
Nice to see also that is the result of a USA-Iran collaboration.