First commercial curved CMOS sensor from startup CURVE
image-sensors-world.blogspot.com
image-sensors-world.blogspot.com
The curvature goes in the opposite direction of what I would have thought. I would've thought the orientation of the curve was in the sense of maintaining a "constant radius" from the end of the lens stack. (exit pupil?) I.e. the curve helps bring in the distant parts of the sensor closer and more orthogonal to the light rays.
But the diagram shows the opposite kind of curve! That makes even less intuitive sense to me.
(I can't imagine someone not involved with the company creating this diagram, or it being so wrong and not being caught by some review process? I figure the diagram is legit? Someone drawing ray tracing level details would get it so wrong?)
Also from the same DPReview article: "Curved image sensors mimic the human eye", that illustration is not how I thought the retina is shaped.
The illustration with simplified optics shows a convex sensor.
Hard to figure it out.
I would imagine chromatic abberation and light dropoff is due to flat sensors and concave sensors would help. But I might not understand modern lens design.
Yet submitting a design to a commercial fab and saying "make it curved plz" isn't likely to work either.
So how is this done?
(Ie. You can curve it around a cylinder, but not around a sphere)
If you could take a flat surface and have it represent the surface of a sphere without warping (or vice-versa), we wouldn't have constant debates about what kind of map projections are best.
There are at least two challenges, one is curve itself, and the other is laying out the sensor to be linear across the curved surface. I'm wondering if they are going to do a Hot Chips presentation, that has been where most of the coolest advances in chip making have been detailed.
A friend speculated they might be doing a mems sort of thing where they make a 'thick' chip and then etch down to the layers of sensors, perhaps polishing, as a glass lens might be made, but for me that seems like it would be too risky. Thinning and bending is a possibility of course you need to account for the final topology in your layout.
Definitely a fun puzzle to speculate about.
Edit: I think "the first one" is the claim for "very first commercial curved sensor for a scientific application"..."for a scientific application" they said, Sony was a selfie camera :-)
Source: https://en.wikipedia.org/wiki/Image_sensor_format#Table_of_s...
Do they start with a curved piece of silicon and do the fabbing on that? Or is it initially flat and then bent during the process?
Will this be generally isolated to very specialty wide-field imaging? And expensive, custom runs?
It looks like their US patent is here: https://patentimages.storage.googleapis.com/10/b3/ee/69d396b...
By the way, this brings back thoughts how astronomy used to be done with thin glass plates, doing wide area sky surveys. The plates would be placed into the plate holder, and some pressure was necessary to deform the plate to match the curvature desired.
They said you knew when you'd gone to far because you'd hear the tinkle of broken glass...
(they also baked the plates in hydrogen to increase their light sensitivity)
We may be back to vacuum tubes again soon:
https://spectrum.ieee.org/semiconductors/devices/introducing...
EDIT: I don’t mean this in a negative manner, I just don’t know about this kind of stuff so I’m curious about what settings this is useful.
A curved sensor should improve optics by limiting distortion. So basically it can take better pictures.
So while it seems reasonable that you could thin down a digital circuit and have it continue to function correctly when bent, a CMOS sensor is a very analog device. I wonder if noise / dark current / other properties vary depending on where the stresses are applied.