PRWeb, VentureBeat: Pixim announced the acquisition of Advasense. Advasense was founded with the vision of dramatically improving the image quality of cameras used in mobile applications.
Currently, Pixim is experiencing exponential sales growth driven by the release of Seawolf, its latest chip product. The Advasense team ideally complements Pixim in the areas of image sensor-specific product design and will be immediately integrated into Pixim’s existing product development organization. This is expected to allow the company to further accelerate its strong sales growth.
The technology of the two companies is highly complementary. For instance, the current push for higher resolution cameras in the video security market demands higher-performance small pixels that do not compromise image quality. Advasense’s development of deep photodiodes significantly enhances pixel well capacity, improving image quality in all lighting conditions even as pixel sizes get smaller.
Wednesday, June 15, 2011
Hynix News
In what looks like a flashback to early 2000s, Hynix announced Hi-QD1, a 1/13-inch QVGA SoC based on 3.2um pixels. Customer samples are available now and volume production will be started in July while its validation tests are going well at major chipset makers. The article says: "With launching this Hi-QD1, Hynix steps into a good business opportunity of CMOS image sensor market." To me this sounds like a production of some Siliconfile's old product has been moved from Dongbu to Hynix fab.
Sys-Con Media: In an unrelated news, Scalado announced that Hynix has licensed its SpeedTags technology. It will now be integrated with Hynix's image sensor products in order to help manage the larger files produced by the latest high-resolution image sensors.
Sys-Con Media: In an unrelated news, Scalado announced that Hynix has licensed its SpeedTags technology. It will now be integrated with Hynix's image sensor products in order to help manage the larger files produced by the latest high-resolution image sensors.
Tuesday, June 14, 2011
Confessions, Confessions
The ISCAS 2011 has had a confession session talking about design mistakes. There are few confessions about image sensor mistakes:
Confession 10: A bipolar imager with one giant pixel
Tobi Delbruck, University of Zurich and ETH Zurich
In 1996 at National Semiconductor and Synaptics in an enterprise that was later to become Foveon we were trying to build a new type of image sensor which Carver Mead invented. It was based on pulsed bipolar phototransistors (Fig. 7, Delbruck et. al, 1997). These pixels required developing our own “poly emitter” bipolar process with vertical NPN bipolar transistors and poly emitters, where the base region was self-aligned by the thin oxide regions. After we got the sensor back from fab, we tried to make it work for many weeks, but could never see any image! The pressure was on. All the circuits seemed to be working but all we could see was that the "picture" changed brightness depending on the light intensity. Dick Merrill finally figured it out. He examined the hundreds of lines of detailed process specifications and noticed that the base implant had been set to 400keV rather than 40keV: The base implant was penetrating right through the field oxide so that we had built one single giant photodiode! I still remember the meeting in a center. Dick said something like “Any idiot would know that 400keV penetrates through FOX!” Well, at that point I certainly didn’t know it, but nodded my head wisely as if I did. Anyhow, instead of an image sensor with 4 million pixels, we had one giant pixel measuring 4mm by 4mm! Eventually we got it all to work, but after many rounds of silicon we concluded that the FPN in the bipolar gain and the image lag (because the base is never fully reset) was a killer and Foveon went in their storied direction of vertical color separation (Gilder 2005).
Moral? Even an experienced team can be tripped up by a typo.
Confession 11: Metal density rules are there for a reason
Tobi Delbruck, University of Zurich and ETH Zurich
During the early days of imager company Foveon we were working closely with National Semiconductor on process development and were turning a new wafer lot at least once a month (Gilder, 2005). This was in the days of 250nm fab development and the fab guys were using us as testers for their process development. We kept having problems with reliable metal in the pixel arrays. It seemed as though the wires were just not making it across the array, or shorting to each other. Finally, a meeting with the group doing the fab development cleared up the mystery: Our pixel arrays just didn't have enough metal in them. As a result, the chemical mechanical polishing (CMP) was leaving the surface of the array at a different height than the periphery, so that the lithography equipment, which focused using the alignment markers at a corner of the chip, was putting the array out of focus. This defocus blurred out the resist exposure, leading to bad metal. Even the very experienced crew of professionals didn’t consider the reason for this metal density rule. CMP was pretty new then, but it didn’t help that (as usual) the design rule documentation gave no reasons for any of the rules.
Moral – Design rules have a physical basis. DR documents should provide a bit of motivation to the designers for following the rules.
Confession 15: Don't cough up your core technology
Tobi Delbruck, University of Zurich and ETH Zurich
In forming a development agreement with an industry partner, we had the bright idea that they might be able to help us pay for chip fabrication. That would have been fine except that we also let them manage the actual submission and direct payment of the run. As a result, they got the chips and the full layout of our sensor and were in a position that they could re-fabricate the design, even without asking us - which they did. We were left in a position of having to buy our own design from another party instead of having them buy it from us.
Moral – Consider how your technology will be used if you let someone else have it.
Confession 9: Beware of parasitic photodiodes in CMOS image sensor design
M. K. Law and A. Bermak, Hong Kong University of Science and Technology
We designed an image sensor array with a fixedpattern-noise (FPN) reduction scheme that required no calibration current source. We modeled the expected photocurrents in each pixel photodiode during simulation and everything worked great. We expected the FPN after correlated double sampling (CDS) should be improved by a factor of 15 to 20. However, measurement results showed that there was only an approximately 2 or 3 times improvement. After a long and tedious debugging process, we finally realized the problem was caused by the fact that the pixel output was also light dependent even during calibration. What we overlooked is that there are also PN-junctions in other pixel transistors (Fig. 6). In that case, they are also photodiodes when illuminated with light, but we did not include this effect in the simulation!! We should have noticed this effect and put dummy metal over the transistors to shield incoming light. Fortunately we can use some post processing techniques at the sensor output to improve the overall FPN.
Moral – You have to fully understand your circuit before running simulations. Most importantly, never blindly believe in simulation results.
Confession 20: Address Decoding Glitches Reset Pixel
Shoushun Chen, Nanyang Technological University
In 2008 we designed and fabricated a motion detection image sensor using an address counter and decoder. The motivation to use an address counter instead of a scanner is to obtain flexibility in reading out regions of interest. However, we found that in the captured image there were a few rows of pixels having abnormal brightness, or row based mismatch. We also found that the error increased with integration time. At the beginning we thought the problem was due to power supply noise. Finally we realized that the error came from glitches of the decoder, which resets the pixel in the middle of integration (Fig. 10). We finally confirmed the mistake in post layout simulation.
Moral – Firstly, without special delay balancing techniques, the decoder always produces glitches. Secondly, the reset node of the pixel is highly sensitive. Any glitch applied to this node will destroy the integration signal. The decoded row/column reset signal should be resynchronized using a register to filter the glitch.
If anyone wants to confess in his/her mistakes too, please do so in comments. In case a figure needs to be added, email me and I'll publish your confession in a separate post.
Confession 10: A bipolar imager with one giant pixel
Tobi Delbruck, University of Zurich and ETH Zurich
In 1996 at National Semiconductor and Synaptics in an enterprise that was later to become Foveon we were trying to build a new type of image sensor which Carver Mead invented. It was based on pulsed bipolar phototransistors (Fig. 7, Delbruck et. al, 1997). These pixels required developing our own “poly emitter” bipolar process with vertical NPN bipolar transistors and poly emitters, where the base region was self-aligned by the thin oxide regions. After we got the sensor back from fab, we tried to make it work for many weeks, but could never see any image! The pressure was on. All the circuits seemed to be working but all we could see was that the "picture" changed brightness depending on the light intensity. Dick Merrill finally figured it out. He examined the hundreds of lines of detailed process specifications and noticed that the base implant had been set to 400keV rather than 40keV: The base implant was penetrating right through the field oxide so that we had built one single giant photodiode! I still remember the meeting in a center. Dick said something like “Any idiot would know that 400keV penetrates through FOX!” Well, at that point I certainly didn’t know it, but nodded my head wisely as if I did. Anyhow, instead of an image sensor with 4 million pixels, we had one giant pixel measuring 4mm by 4mm! Eventually we got it all to work, but after many rounds of silicon we concluded that the FPN in the bipolar gain and the image lag (because the base is never fully reset) was a killer and Foveon went in their storied direction of vertical color separation (Gilder 2005).
Moral? Even an experienced team can be tripped up by a typo.
Confession 11: Metal density rules are there for a reason
Tobi Delbruck, University of Zurich and ETH Zurich
During the early days of imager company Foveon we were working closely with National Semiconductor on process development and were turning a new wafer lot at least once a month (Gilder, 2005). This was in the days of 250nm fab development and the fab guys were using us as testers for their process development. We kept having problems with reliable metal in the pixel arrays. It seemed as though the wires were just not making it across the array, or shorting to each other. Finally, a meeting with the group doing the fab development cleared up the mystery: Our pixel arrays just didn't have enough metal in them. As a result, the chemical mechanical polishing (CMP) was leaving the surface of the array at a different height than the periphery, so that the lithography equipment, which focused using the alignment markers at a corner of the chip, was putting the array out of focus. This defocus blurred out the resist exposure, leading to bad metal. Even the very experienced crew of professionals didn’t consider the reason for this metal density rule. CMP was pretty new then, but it didn’t help that (as usual) the design rule documentation gave no reasons for any of the rules.
Moral – Design rules have a physical basis. DR documents should provide a bit of motivation to the designers for following the rules.
Confession 15: Don't cough up your core technology
Tobi Delbruck, University of Zurich and ETH Zurich
In forming a development agreement with an industry partner, we had the bright idea that they might be able to help us pay for chip fabrication. That would have been fine except that we also let them manage the actual submission and direct payment of the run. As a result, they got the chips and the full layout of our sensor and were in a position that they could re-fabricate the design, even without asking us - which they did. We were left in a position of having to buy our own design from another party instead of having them buy it from us.
Moral – Consider how your technology will be used if you let someone else have it.
Confession 9: Beware of parasitic photodiodes in CMOS image sensor design
M. K. Law and A. Bermak, Hong Kong University of Science and Technology
We designed an image sensor array with a fixedpattern-noise (FPN) reduction scheme that required no calibration current source. We modeled the expected photocurrents in each pixel photodiode during simulation and everything worked great. We expected the FPN after correlated double sampling (CDS) should be improved by a factor of 15 to 20. However, measurement results showed that there was only an approximately 2 or 3 times improvement. After a long and tedious debugging process, we finally realized the problem was caused by the fact that the pixel output was also light dependent even during calibration. What we overlooked is that there are also PN-junctions in other pixel transistors (Fig. 6). In that case, they are also photodiodes when illuminated with light, but we did not include this effect in the simulation!! We should have noticed this effect and put dummy metal over the transistors to shield incoming light. Fortunately we can use some post processing techniques at the sensor output to improve the overall FPN.
Moral – You have to fully understand your circuit before running simulations. Most importantly, never blindly believe in simulation results.
Confession 20: Address Decoding Glitches Reset Pixel
Shoushun Chen, Nanyang Technological University
In 2008 we designed and fabricated a motion detection image sensor using an address counter and decoder. The motivation to use an address counter instead of a scanner is to obtain flexibility in reading out regions of interest. However, we found that in the captured image there were a few rows of pixels having abnormal brightness, or row based mismatch. We also found that the error increased with integration time. At the beginning we thought the problem was due to power supply noise. Finally we realized that the error came from glitches of the decoder, which resets the pixel in the middle of integration (Fig. 10). We finally confirmed the mistake in post layout simulation.
Moral – Firstly, without special delay balancing techniques, the decoder always produces glitches. Secondly, the reset node of the pixel is highly sensitive. Any glitch applied to this node will destroy the integration signal. The decoded row/column reset signal should be resynchronized using a register to filter the glitch.
If anyone wants to confess in his/her mistakes too, please do so in comments. In case a figure needs to be added, email me and I'll publish your confession in a separate post.
PerkinElmer Acquires Dexela
Business Wire: PerkinElmer announced that it has acquired Dexela, a London, UK-based provider of flat panel CMOS X-ray detection technologies and services. Founded in 2005, Dexela develops and commercializes its CMOS technology portfolio for fast, low-dose X-ray imaging. The company’s CMOS products offer high spatial resolution frame rate and reliability, low noise and absence of image lag.
"Dexela has been a pioneer in the development of CMOS X-ray detection solutions and has achieved award-winning recognition in the imaging market for its design strengths and ease of manufacturability – which are major advantages for OEM customers," said Brian Giambattista, President, Medical Imaging, PerkinElmer.
"Dexela has been a pioneer in the development of CMOS X-ray detection solutions and has achieved award-winning recognition in the imaging market for its design strengths and ease of manufacturability – which are major advantages for OEM customers," said Brian Giambattista, President, Medical Imaging, PerkinElmer.
Monday, June 13, 2011
Ambarella Files for IPO
EETimes, Business Wire: Ambarella announced that it has filed a registration statement for a proposed IPO. The number of shares to be offered and the price range for the offering have not yet been determined. Morgan Stanley and Deutsche Bank are acting as the joint book-running managers for the offering. Stifel, Nicolaus & Company and Needham & Company are acting as co-managers for the offering.
So, soon we might have a second publicly traded company specializing in image processors. The first one was Mtekvision, traded on KOSDAQ.
Thanks to S.S. for sending me the news!
So, soon we might have a second publicly traded company specializing in image processors. The first one was Mtekvision, traded on KOSDAQ.
Thanks to S.S. for sending me the news!
Saturday, June 11, 2011
News from IISW 2011
I received these announcements from Eric Fossum:
June 10, 2011
News from the 2011 International Image Sensor Workshop in Hokkaido, Japan
The parent organization of the 2011 IISW is changing its name to the International Image Sensor Society, Inc., from ImageSensors, Inc. The renamed organization, IISS, also has added two directors to its Board – Junichi Nakamura and Johannes Solhusvik. They join Eric Fossum, Albert Theuwissen and Nobukazu Teranishi.
The IISS will become a member-based Professional Society and will solicit members in the coming months. In addition to sponsoring the biennial IISW and the Walter Kosonocky Award, plans for an on-line open-access peer-reviewed IISS Journal of Image Sensors are being developed by Dr. Solhusvik. It is hoped that cooperation with other professional societies such IEEE, SPIE or OSA can be implemented.
At the 2011 IISW, it was announced that the winner of the 2011 Walter Kosonocky Award is Hayato Wakabayashi and his co-authors from Sony Corporation for the paper titled “A 1/2.3-inch 10.3Mpixel 50frame/s Back-Illuminated CMOS Image Sensor” which was presented at the 2010 IEEE International Solid-State Circuits Conference.
A new award has been established by the International Image Sensor Society for Exceptional Service. The 2011 IISS Exceptional Service Award was presented to Vladimir Koifmann for the creation and editorship of the Image Sensors World blog, which has proved to be valuable for many in the image sensor community. Mr. Koifman is currently with AdvaSense in Israel.
The International Image Sensor Society congratulates its award winners on achieving excellence and contributing to the image sensor community.
June 10, 2011
News from the 2011 International Image Sensor Workshop in Hokkaido, Japan
The parent organization of the 2011 IISW is changing its name to the International Image Sensor Society, Inc., from ImageSensors, Inc. The renamed organization, IISS, also has added two directors to its Board – Junichi Nakamura and Johannes Solhusvik. They join Eric Fossum, Albert Theuwissen and Nobukazu Teranishi.
The IISS will become a member-based Professional Society and will solicit members in the coming months. In addition to sponsoring the biennial IISW and the Walter Kosonocky Award, plans for an on-line open-access peer-reviewed IISS Journal of Image Sensors are being developed by Dr. Solhusvik. It is hoped that cooperation with other professional societies such IEEE, SPIE or OSA can be implemented.
At the 2011 IISW, it was announced that the winner of the 2011 Walter Kosonocky Award is Hayato Wakabayashi and his co-authors from Sony Corporation for the paper titled “A 1/2.3-inch 10.3Mpixel 50frame/s Back-Illuminated CMOS Image Sensor” which was presented at the 2010 IEEE International Solid-State Circuits Conference.
A new award has been established by the International Image Sensor Society for Exceptional Service. The 2011 IISS Exceptional Service Award was presented to Vladimir Koifmann for the creation and editorship of the Image Sensors World blog, which has proved to be valuable for many in the image sensor community. Mr. Koifman is currently with AdvaSense in Israel.
The International Image Sensor Society congratulates its award winners on achieving excellence and contributing to the image sensor community.
Cambridge Mechatronics Proposes OIS Performance Measure
Cambridge Mechatronics (CML) proposes a performance measure for image stabilization systems, described in the company's whitepaper here. Ben Brown, the paper's author, presents nice graphs of measured handshake:
One can see that a long term handshake fits within +/-0.5 deg range. I seem to recall some old Kodak data saying it's more like +/-2 deg, but this should be very camera-dependent. In any case, Cambridge Mechatronics actuator shows impressive capability to reduce it and even compared with a Canon 70-200mm f/4L SLR lens.
The paper concludes:
"The performance of CML’s 8.5mm x 8.5mm SMA OIS camera-Tilt (SOT) actuator offers around 2 stops more suppression than the Canon 70-200mm lens. This is most likely due to the high resonant frequency afforded by the high stiffness of the SMA actuator and the small mass of miniature cameras. This is an advantage that miniature cameras have over larger cameras which will allow OIS to have a very significant performance impact in smartphones."
Thanks to DW for sending me the link!
One can see that a long term handshake fits within +/-0.5 deg range. I seem to recall some old Kodak data saying it's more like +/-2 deg, but this should be very camera-dependent. In any case, Cambridge Mechatronics actuator shows impressive capability to reduce it and even compared with a Canon 70-200mm f/4L SLR lens.
The paper concludes:
"The performance of CML’s 8.5mm x 8.5mm SMA OIS camera-Tilt (SOT) actuator offers around 2 stops more suppression than the Canon 70-200mm lens. This is most likely due to the high resonant frequency afforded by the high stiffness of the SMA actuator and the small mass of miniature cameras. This is an advantage that miniature cameras have over larger cameras which will allow OIS to have a very significant performance impact in smartphones."
 |
| CML SMA Camera Module, 8.5mm x 8.5mm, AF + OIS |
Thanks to DW for sending me the link!
Friday, June 10, 2011
Albert Theuwissen Overviews IISW, Day 1
Albert Theuwissen published a nice overview of the first day of IISW 2011.
TYZX Demo Shows Passive Stereo 3D Technoogy in Action
The Youtube video below possibly shows passive stereo 3D vision limitation - only high-contrast objects are visible on the depth map. Probably the flat panels of cubicles and walls do not have a sufficient contrast:
Subscribe to:
Posts (Atom)