3 ms·

> Digital sensors these days are way better at capturing light Has the quantum efficiency of silicon improved? How much?

analog31 4y ago
Not quantum efficiency per se, but dynamic range has been improved by the development of sensors with lower readout noise.
- robomartin 4y ago
  The statement was that today’s sensors are “better at capturing light”. Not sure signal-to-noise is what the OP meant. Note: I studied CCD and CMOS sensor design some 15 years ago under the scientists who designed a great deal of the sensors that flew in spacecraft. Jim Janesick was one of my instructors. https://www.amazon.com/Books-James-R-Janesick/s?rh=n%3A283155%2Cp_27%3AJames+R.+Janesick https://www.amazon.com/Books-James-R-Janesick/s?rh=n%3A28315...
  - mulmen 4y ago
    Well they said today's sensors, not today's silicon. The favorable reading is that the sensor is considered as a component.
    - robomartin 4y ago
      > The favorable reading is that the sensor is considered as a component. No. It's about materials properties and physics.
mulmen 4y ago
A camera sensor isn’t just a piece of silicon. It is a complex manufactured component. It’s possible to create a camera sensor that isn’t limited by the quantum efficiency of silicon. In fact, it’s likely that no sensor is “perfect” and that tradeoffs are made between cost and suitability for purpose. My 2010 BMW gets better gas mileage at higher speeds than my 1973 Oldsmobile, even though the energy density of a gallon of gasoline hasn’t changed. And neither of them is anywhere near the theoretical maximum.
- robomartin 4y ago
  > It’s possible to create a camera sensor that isn’t limited by the quantum efficiency of silicon Well, the QE pretty much is the limit. Sorry.
  - mulmen 4y ago
    You misunderstand. I mean that something else will limit the capability of the sensor before the quantum efficiency of the silicon. In other words it is not a practical limit. Some cost/quality control, manufacturing process, or data interface is instead.
    - robomartin 4y ago
      > I mean that something else will limit the capability of the sensor before the quantum efficiency of the silicon. Sorry. Again, no. Not a single well designed camera will do this. Quantum efficiency is, to use a term from a time gone by, the "emulsion". Now, if you are talking about a $15 security camera or some garbage design, sure, whatever, anything is possible. I have been involved in the design of cameras for terrestrial, orbital and lunar applications. You don't throw anything away unless you absolutely have to. QE is the "fingerprint" of the sensor, it si based on the material used to make it and it all follows from there. Put a different way, it's how a sensor converts photons landing on a pixel into electrons. You can't degrade or enhance this externally. If less photons land on the pixel (bad optics, ND filters, etc.) the QE is the same. If more photons hit the pixel (back illumination, better optics, etc.) the QE is the same. If you have shitty digital processing, the QE is the same. Etc. Going back to statement that "Digital sensors these days are way better at capturing light", still not sure what it means. For example, a better way to capture light is back illumination, which has been around for many decades. Interested in learning if there's something in modern sensors (in production) I might not know about. I have a database of nearly every imaging sensor in production up to about a year go. It covers the SWIR to visible range. Every sensor you can buy. If there are any advancements that cause a sensor to be "way better at capturing light", I would sure love to know about it.

analog31 4y ago

Not quantum efficiency per se, but dynamic range has been improved by the development of sensors with lower readout noise.

robomartin 4y ago
The statement was that today’s sensors are “better at capturing light”. Not sure signal-to-noise is what the OP meant. Note: I studied CCD and CMOS sensor design some 15 years ago under the scientists who designed a great deal of the sensors that flew in spacecraft. Jim Janesick was one of my instructors. https://www.amazon.com/Books-James-R-Janesick/s?rh=n%3A283155%2Cp_27%3AJames+R.+Janesick https://www.amazon.com/Books-James-R-Janesick/s?rh=n%3A28315...
- mulmen 4y ago
  Well they said today's sensors, not today's silicon. The favorable reading is that the sensor is considered as a component.
  - robomartin 4y ago
    > The favorable reading is that the sensor is considered as a component. No. It's about materials properties and physics.

mulmen 4y ago

A camera sensor isn’t just a piece of silicon. It is a complex manufactured component. It’s possible to create a camera sensor that isn’t limited by the quantum efficiency of silicon. In fact, it’s likely that no sensor is “perfect” and that tradeoffs are made between cost and suitability for purpose. My 2010 BMW gets better gas mileage at higher speeds than my 1973 Oldsmobile, even though the energy density of a gallon of gasoline hasn’t changed. And neither of them is anywhere near the theoretical maximum.

robomartin 4y ago
> It’s possible to create a camera sensor that isn’t limited by the quantum efficiency of silicon Well, the QE pretty much is the limit. Sorry.
- mulmen 4y ago
  You misunderstand. I mean that something else will limit the capability of the sensor before the quantum efficiency of the silicon. In other words it is not a practical limit. Some cost/quality control, manufacturing process, or data interface is instead.
  - robomartin 4y ago
    > I mean that something else will limit the capability of the sensor before the quantum efficiency of the silicon. Sorry. Again, no. Not a single well designed camera will do this. Quantum efficiency is, to use a term from a time gone by, the "emulsion". Now, if you are talking about a $15 security camera or some garbage design, sure, whatever, anything is possible. I have been involved in the design of cameras for terrestrial, orbital and lunar applications. You don't throw anything away unless you absolutely have to. QE is the "fingerprint" of the sensor, it si based on the material used to make it and it all follows from there. Put a different way, it's how a sensor converts photons landing on a pixel into electrons. You can't degrade or enhance this externally. If less photons land on the pixel (bad optics, ND filters, etc.) the QE is the same. If more photons hit the pixel (back illumination, better optics, etc.) the QE is the same. If you have shitty digital processing, the QE is the same. Etc. Going back to statement that "Digital sensors these days are way better at capturing light", still not sure what it means. For example, a better way to capture light is back illumination, which has been around for many decades. Interested in learning if there's something in modern sensors (in production) I might not know about. I have a database of nearly every imaging sensor in production up to about a year go. It covers the SWIR to visible range. Every sensor you can buy. If there are any advancements that cause a sensor to be "way better at capturing light", I would sure love to know about it.