IsInvariant Proposes New Sensor Technology

I was given a presentation from IsInvariant - a new start-up company proposing its own way to make sensors:

Value Proposition

IsInvariant™ is introducing a pixel preamplifier to increase dynamic range while decreasing power consumption, chip real-estate, and noise

Dynamic Range of Camera, Comparison of Systems

• Ordinary Camera – 48 dB
• High End Camera – 96 dB
• Logarithmic Camera – 120dB
• Humans – 80dB with biasing 200dB

Noise in Cameras

• Logarithmic cameras suffer from high NEP (Noise Equivalent Power) that arises partly from biasing the pixel PN junction
• Humans have the remarkable characteristic of being able to sense single photon events, as if the visual apparatus operates with no NEP

Ideal Camera Characteristics

• Unbiased PN Junction
• Logarithmic from one photon to ten billion photons per second
• Insignificant power consumption

Pre-Amplifier in Image Sensor

Use of Pre-Amplifier

• A PN junction converts photons into electron/hole pairs
• A preamplifier converts pairs into usable measurements

An Ideal Pre-Amplifier

• Converts input light intensity into logarithmic output signal
• Covers theoretical 200 dB range without introducing or amplifying noise

Current Technology Limitations

Biasing of PN Junction

• Johnson noise and consumption of DC current, reduces effective range
• Dynamic ranges of pre-amplifiers bounded by absolute “noise floor” and “saturation”

Crux of Problem

• Camera image planes fail to exploit full dynamic range of PN Junction sensors
• Available preamplifiers force an artificial saturation
• Johnson noise

IsInvariant's Solution:

IsInvariant Pre-Amplifier

• Exploits full dynamic range of PN Junction
• Enables low-noise transduction of the entire photosensor dynamic range
• Consumes less power

Pending Patents

• 20050036655 - Imaging system (Continuation in part)
• 20050104632 - Geometric remapping with delay lines
• 7796173 - Imaging system (Issued September 14, 2010)

Few performance slides:

The traces apparently relate to a pixel structure shown below:

Advantages of IsInvariant's Solution

• Dynamic range increases over current preamplifiers (from 120 dB to 200 dB)
• Power requirements will decrease (no DC current)
• VLSI masking complexity will decrease (no OpAmp)
• Chip die size will decrease (small silicon footprint)
• No camera flash needed (no bias-related noise floor)
• Time-to-market is driven by manufacturer remasking (no retooling needed)

IISW 2011 Call For Paper Posted

2011 International Image Sensor Workshop (IISW) Call For Paper has been posted. The deadline for receipt of abstracts is January 17, 2011. The Workshop will be held at Hakodate-Onuma Prince Hotel, Hokkaido Prefecture, Japan, June 8-11, 2011.

RTS Noise in Pixels Explored

The new part in Albert Theuwissen's PTC series covers RTS noise in pixels and how it affects PTC. The conclusion is simple: "the presence of the RTS pixels has no major influence on the PTC curve. All parameters extracted are very similar to a simulation without RTS pixels. To detect the characteristics of the RTS pixels, other tools than the PTC need to be applied."

IMEC Starts 3SIS Project

IMEC initiated an ambitious Flemish 3SIS Strategic Basic Research (SBO) project with aim to come up with a 3D integrated CMOS imager consisting of vertically integrated optical/detector/analog/digital processing tiers.

With respect to process technology the project will focus on:

1. 3D integration technology with through-silicon vias, allowing a separation of the photodetectors on the one hand and the pixel read-out electronics on the other hand into 2 separate layers.
2. Technologies for more sensitive pixels
3. Pixel sensitivity for wavelengths outside the visual light spectrum.
4. Microlenses that are optimized for NIR and UV as well as visual light and that offer additional functionalities

Thanks to P.R. for sending me the link!

e2v Sensor to Map the Geometry of the Dark Universe

e2v has been awarded a contract to develop a new CCD for the ESA Euclid space science mission. The aim of the mission is to map and survey the shapes of galaxies to investigate the geometry of the dark universe through weak gravitational lensing.

Weak gravitational lensing requires extremely high image quality to measure the true distortions by gravity. e2v’s image sensors will form the visible focal plane array in the Euclid space telescope. The CCDs will be large area back illuminated devices optimised for 550-920nm. The devices will be manufactured for close-buttability to minimise dead area in the focal plane and reduce the telescope size, mass and cost.

Another good news message from e2v says that its facility in Grenoble, France has responded to increased demand within the line scan camera business by increasing its temporary workforce and implementing new shift patterns that better utilise equipment which has led to greatly increased productivity.

Positive trends within the machine vision industry have led to significant increased demand for e2v’s camera products that have been introduced over the last two years. The temporary operators and test lines are already up and running and have already doubled e2v’s production capacity.

TSMC Enjoys Strong CMOS Sensor Sales

Taipei Times: TSMC is said to have strong image sensor sales in Q3:

“We believe the strength in September, or the third quarter, was mainly from CDMA, wireless, CMOS image sensor and handset names,” said Roland Shu, a semiconductor analyst with Citigroup, in his report. Yesterday TSMC surprised many analysts when reported record high monthly September sales, bringing its third-quarter revenue slightly above the company’s forecast.

Hynix Announced 2MP ShellUT-Packaged Sensor

Hynix Sept. 2010 Newsletter has an announcement of 1/5-inch 2M ShellUT-packaged sensor for mobile phone and notebook PC camera applications. The sensor is based on 1.75um pixel and has an integrated ISP. Its frame rate is 15fps at full resolution.

According to the newsletter, the mass production of the imager has started in August, while the system validation has been completed in Spetember 2010.

Sony Introduces 1.12um BSI Pixels, New Sensors, Modules

Sony announced the commercialization of two new "Exmor R" BSI sensors: 1.12um-based 16.4MP IMX081PQ and 1.4um-based 8.1MP IMX105PQ, both specifically designed for mobile phones.

The most interesting one, IMX081PQ, is presented as the world's first type 1/2.8-inch BSI sensor which realizes 16.41MP effective resolution, and adopts unit pixel size of 1.12μm. Sony says to implement "a unique formation of photo diodes optimally designed for fine pixel structure to realize a CMOS image sensor with high resolution, high sensitivity and low noise". The picture below shows the resolution improvement:

The second sensor, IMX105PQ, is a type 1/3.2-inch BSI sensor which realizes 8.13MP effective resolution and adopts a unit pixel size of 1.4μm. The 20Lux illumination comparison picture is below (using the newly announced camera module):

Furthermore, Sony will commercialize IU081F and IU105F2 AF camera-modules which include the two new sensors. IU081F is said to be the industry's smallest and thinnest AF module (W10.5 X D10.5 X H7.9mm) and is equipped with the 16.41MP sensor. IU105F2 adopts the 8.13MP sensor, and is said to belong in the industry's smallest and thinnest size class (W8.5 X D8.5 X H5.67mm):

The table gives a few spec details foe the new sensors and modules:

Sensors:

Model Name IMX081PQ IMX105PQ Number of effective pixels 4672(H)×3512(V) 16.41M pixels 3288(H)×2472(V) 8.13M pixels Image size Diagonal 6.5mm (Type1/2.8) square pixel Diagonal 5.76mm (Type 1/3.2) square pixel Unit cell size 1.12μm□ 1.4μm□ Frame rate Full 15fps 15fps 1/2 sub sampling 30fps 30fps 1/8 sub sampling 120fps 120fps HD mode 1080-30P / 720-60P 1080-30P / 720-30P Sensitivity 205 digit (10Bit) 310 digit (10Bit) Saturation signal 820 digit (10Bit) 1023 digit (10Bit) Power supply Analog 2.7 +0.2/-0.1V 2.7 +0.2/-0.1V Digital 1.2 ±0.1V 1.2 ±0.1V Interface 1.8 ±0.1V 1.8 ±0.1V Major function 3-wire serial communication, I2C, serial data output, supports flexible input clock Output MIPI 4,2,1 Lane MIPI 2,1 Lane

Camera modules data:

Model Name	IU081F (16.4MP)	IU105F2 (8.1MP)
Module size*2	10.5(W)×10.5(D)×7.9(H)mm	8.5(W)×8.5(D)× 5.67(H)mm
AF actuator	Voice coil motor
Lens construction	4 groups 4 elements (Plastic)
F-number	F2.6	F2.4
Focal length (35mm conversion)	28mm
Camera output	MIPI (4 Lane)	MIPI (2 Lane)

The samples availability and prices are given below:

Model Name	Shipment date (Plan)	Sample price
Type 1/2.8 16.41 effective megapixels back-illuminated CMOS image sensor "IMX081PQ"	January, 2011	2,500 JPY
Type 1/3.2 8.13 effective megapixels back-illuminated CMOS image sensor "IMX105PQ"	April, 2011	1,500 JPY
Type 1/2.8 16.41 effective megapixels Lens module "IU081F"	March, 2011	12,000 JPY
Type 1/3.2 8.13 effective megapixels Lens module "IU105F2"	April, 2011	8,000 JPY

At the end of 2010, Sony plans to start the mass production of BSI sensors, including those for mobile phones announced today, at Sony Semiconductor Kyushu Corporation's Kumamoto Technology Center, on 300mm wafer lines. Sony already announced on Sept. 1, 2010 the investment of approximately 40 billion yen in Kumamoto Technology Center to increase production capacity for CMOS image sensors.

Sony Semiconductor Kyushu Corporation's Kumamoto Technology Center

Interview with Foveon Executives

DPReview published an interview with Sigma COO Kazuto Yamaki, Foveon VP for Technology and Operations, Shri Ramaswami and its VP for Strategic Marketing, Rudy Guttosch talking about challenges on new 15.4x3 MP sensor design. The new sensor will be at the heart of the Sigma new SD1 DSLR, which is due in early 2011.

Other than talking about the new sensor design, the article also mentions Foveon's past project of a sensor for mobile phone.

Sony is Accused of Infringing L-3 Communications Patents

Bloomberg: Sony was sued by a unit of U.S. defense contractor L-3 Communications Holdings Inc. and accused of infringing two patents for image sensors, 5,541,654 and 5,452,004, which were issued in September 1995 and July 1996, respectively.

L-3 asked for a jury trial, unspecified damages and a permanent injunction against infringing products, in an Aug. 27 lawsuit in federal court in Wilmington, Delaware. The New York-based company’s “extensive patent portfolio protects L-3’s considerable investment in its research-and- development efforts,” and Sony should pay license fees, L-3 said in court papers.

To me the both patents look similar and quite generic:

#5,541,654 Focal plane array imaging device with random access architecture

Abstract

An imaging device includes an array of plural imaging elements each of which is responsive to incident light flux to provide an output signal. Each of the imaging elements includes provision for conducting a variable time integration of incident light flux, and alternatively, also for selecting a time interval during which each of the imaging elements simultaneously conducts such a time integration of incident light flux (i.e., takes a snap shot of an image scene). The imaging device includes provision for random access of each image element or group of image elements in the array so that output signals indicative of all or of only selected parts of an imaged scene can be processed for their image information, if desired. The other parts of an imaged scene may not be considered or may be considered for their image information at a lower sampling rate than the selected parts of the scene so that image information about the selected parts of the image scene can be accessed at a much higher rate than is conventionally possible. A variable gain feature allows selective canceling of fixed-pattern noise, interference, or unwanted image information. An anti-blooming feature prevents charge from an excessively bright image source from cascading across the array. Also, a control cache memory allows control commands to be fed to the device at a high rate and to be implemented at a slower rate on a first-in, first-out basis.

#5,452,004 Focal plane array imaging device with random access architecture

Abstract

An imaging device includes an array of plural imaging elements each of which is responsive to incident light flux to provide an output signal. Each of the imaging elements includes provision for conducting a variable time integration of incident light flux, and alternatively, also for selecting a time interval during which each of the imaging elements simultaneously conducts such a time integration of incident light flux (i.e., takes a snap shot of an image scene). The imaging device includes provision for random access of each image element or group of image elements in the array so that output signals indicative of all or of only selected parts of an imaged scene can be processed for their image information, if desired. The other parts of an imaged scene may not be considered or may be considered for their image information at a lower sampling rate than the selected parts of the scene so that image information about the selected parts of the image scene can be accessed at a much higher rate than is conventionally possible. A variable gain feature allows selective canceling of fixed-pattern noise, interference, or unwanted image information. An anti-blooming feature prevents charge from an excessively bright image source from cascading across the array. Also, a control cache memory allows control commands to be fed to the device at a high rate and to be implemented at a slower rate on a first-in, first-out basis.

Thanks to J.S. for sending me the link.