Wednesday, February 26, 2020
Quantum Dot Future
IEEE Spectrum: "It’s time for another revolution in imaging technology. This one will be brought to you by the quantum dot, a nanometer-size particle of semiconductor material, which acts much differently from its bulk counterpart."
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"Apple decided to stop the development of QD image sensors because it was too expensive for mass production."
ReplyDeleteNot too long ago, InVisage said they had created quantum dot sensors that performed way better than their CMOS counterparts and also made some short film, allegedly shot on a smartphone with a QD sensor. The video wasn't too impressive to be honest, and after Apple bought the company, all its work disappeared into thin air. And then, Apple finally abandoned the project, completely.
If none of the big image sensor makers have used QT sensors, there must be some good reason why. Price notwithstanding.
Apple is not an image sensor maker. iPhones used sensors manufactured by Omnivision and Sony. Their moves and statements (like buying and shutting down nVisage) are not necessarily dictated by intention of going forward, but dictated by profit. Do not forget that they manufactures crappy but costly produxts products
DeleteIs this: https://www.lanmodo.com/lanmodo-1080p-automotive-night-vision-system.html a thin-film/QD based sensor/camera? Is saying "active infrared" and looks through fog or rain so it must be QD-based?
ReplyDeleteJust wondering what sensor it has if anybody knows?
Maybe Vladimir can make a separate post about this lanmodo camera?
"Active infrared" means it has an infrared lighting source.
DeleteI think QD sensors might be a good match for some NIR and longer wavelength IR sensor applications. Visible - not so much. Lag and low read noise is very important for low light imaging.
ReplyDeleteThere are a lot of approaches towards vision in SWIR wavelength, but are there enough problems for the promising solutions? In the end SWIR is a bit of a niche topic. I doubt it will be "interesting" enough for a mass of consumers to buy, so that the number goes up. The numbers will go up, there will be a lot of new of applications in automation like plastic sorting that will get easier and less costly. But I doubt the world will need millions of SWIR imagers a year. The traditional InGaAs sensor property and cost patterns will change with such kind of cameras. But I doubt we will see SWIR cameras on smartphones (or is my imagination too bad not to see the benefit of it?). Well maybe automotive LIDAR with SWIR lasers or autonomous vehicle topics will bring the volume? What "consumer" need would require imagers with SWIR sensitivity?
ReplyDeleteFaceID already requires millions of SWIR imagers per year. Most phone companies have rejected FaceID-type features due to the notch, but Apple persists with it (which I believe is why they bought InVisage), and Google copies.
DeleteThat's NIR not SWIR. SWIR is not in Face-ID...
Deletereally in SWIR (in my head SWIR starts above the Si bandgap at about 1100nm)? I thought face id runs below that and the CIS is SI based? I was talking about the infrared range above 1100 that is currently covered by ingaas.
DeleteAugmented Reality might be a consumer application needing SWIR sensors.
DeleteQuote, "That's NIR not SWIR. SWIR is not in Face-ID..."
DeleteAh, yes. Of course that is correct. Momentary brain f**t there!
You have just no idea what you are talking about :)
ReplyDeleteThe Bio-Medical applicaiton must have millions+ demand!
ReplyDeleteSWIR you mean? Really?
DeleteUnlike Silicon-based semiconductors, which are mainly SRH (Shockley-Read-Hall) recombination, the p-n junction electron-hole pair recombination in QDs are dominated by Auger recombination.
ReplyDeleteAuger recombination is a non-radiative recombination process that occurs when an electron-hole pair recombines and the excess energy is transferred to another carrier (either an electron or hole) instead of being emitted as a photon. This process can occur in both direct and indirect bandgap semiconductors. Auger recombination is therefore generating heat. In a quantum dot display, Auger heat is more heat on the device, however, in a QD sensor device the Auger heat is noise.