sCMOS Technical FAQs
What color filter options are available on your sensors?
Our color sensors utilize the RGBG Bayer pattern and microlenses. The monochrome sensors also have microlenses. Custom filters are possible on a contractual basis in some cases.
What is the CRA of your microlenses?
Our microlenses are positioned directly on top of the photodiode for all pixels, meaning the CRA is zero degrees for all of our sensors.
Do you have any special treatment on your windows, such as IR filters?
Our glass lids that are permanently mounted on the packages have an AR coating on both sides. For the removable glass lid option those windows have no AR coating. We do not have an IR-cut filter option.
Is an IR-cut filter recommended when using your image sensors?
Typically yes, if your light source contains some near IR wavelengths. For good color reproduction an IR-cut filter is recommended since our color filters do pass some near IR wavelengths. For monochrome applications an IR-cut filter will assist in improving MTF since longer wavelengths can be captured by adjacent pixels due to carrier diffusion.
Why are your specifications for global shutter different than for rolling shutter?
Our global shutter is unique in that is uses fewer transistors than typical global shutter image sensors. This gives us an advantage in full well capacity, sensitivity and read noise over our competitors. However, this has tradeoffs. For global shutter we provide an output of two frames of information; a reset frame and a data frame, making the frame rate ½ that of rolling shutter. Our global shutter implementation also adds to increased dark current and transistor noise versus our rolling shutter mode.
How do we deal with your dual outputs of digital data?
Because we provide simultaneous high gain and low gain data we get excellent dynamic range without any motion artifacts. The camera must “blend” these two data types together for each pixel. Blending can be accomplished several ways, from a simple transition at a set point to a smoother mathematical calculation to ease between the two gain levels. When a customer is proceeding in their camera design we can provide the blending algorithm that we use in our Product Evaluation Kit.
Can I increase the frame rate of your image sensors by reducing the number of pixels read out?
Yes, the frame rate is indirectly proportional to the number of rows you read out. For example, if you reduce the number of rows in half you double the frame rate. The number of columns read out does not affect the frame rate. The amount of time for a row to read out is fixed.
Do you have reference designs available for your sensors?
No. We do not have complete camera reference designs. We do have Product Evaluation Kits (PEKs) available for sale or as loaners for some of our parts. And we do have recommendations for power supply specs, FPGAs, sensor board schematics, sockets, etc.
Do your sensors undergo qualifications?
Yes. Our sensor qualification testing (ESD, HTOL, latchup, etc) are all performed to semiconductor industry JEDEC standards.
Do you have any radiation hardness data on your image sensors?
Several of our sensors have been used in many different applications and environments, including Space applications. Our customers have qualified our sensors and their cameras for these applications and therefore we have not performed these qualifications, nor can we share the data from our customers.