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A curved image sensor
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#2
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A curved image sensor
On Wednesday, July 12, 2017 at 8:46:51 PM UTC-6, RichA wrote:
https://www.dpreview.com/news/186978...e-image-sensor This is exciting, but even when they go into production, this will no doubt only be affordable by major observatories, not amateur astronomers. Likely we're talking six figures here. Of course, perhaps eventually inexpensive manufacturing techniques will be found, such as SOI where the insulating substrate can be heated enough to make it malleable without disturbing the delicate microcircuitry on its surface. Since a sphere is not a reducible surface, though, the interconnects will have to survive stretching. John Savard |
#3
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A curved image sensor
On Wednesday, July 12, 2017 at 11:41:01 PM UTC-4, Quadibloc wrote:
On Wednesday, July 12, 2017 at 8:46:51 PM UTC-6, RichA wrote: https://www.dpreview.com/news/186978...e-image-sensor This is exciting, but even when they go into production, this will no doubt only be affordable by major observatories, not amateur astronomers. Likely we're talking six figures here. Of course, perhaps eventually inexpensive manufacturing techniques will be found, such as SOI where the insulating substrate can be heated enough to make it malleable without disturbing the delicate microcircuitry on its surface. Since a sphere is not a reducible surface, though, the interconnects will have to survive stretching. John Savard Has anyone done any study to see how such a sensor if available to consumer firms would impact lens design? |
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A curved image sensor
On Wednesday, July 12, 2017 at 9:41:01 PM UTC-6, Quadibloc wrote:
Of course, perhaps eventually inexpensive manufacturing techniques will be found, such as SOI where the insulating substrate can be heated enough to make it malleable without disturbing the delicate microcircuitry on its surface. An even more sensible method: Do SOI, but have the insulator already in a curved shape before starting. The optics for going from the mask to the substrate, after all, can *also* be designed to have curvature of field! And then there are no problems with deformation at all. John Savard |
#5
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A curved image sensor
On Thursday, July 13, 2017 at 1:08:08 PM UTC-6, Quadibloc wrote:
On Wednesday, July 12, 2017 at 9:41:01 PM UTC-6, Quadibloc wrote: Of course, perhaps eventually inexpensive manufacturing techniques will be found, such as SOI where the insulating substrate can be heated enough to make it malleable without disturbing the delicate microcircuitry on its surface. An even more sensible method: Do SOI, but have the insulator already in a curved shape before starting. The optics for going from the mask to the substrate, after all, can *also* be designed to have curvature of field! And then there are no problems with deformation at all. Of course, that requires an investment in a very specialized production line. SONY bent their sensor after the fact, as this article notes - https://www.engadget.com/2014/07/08/...curved-sensor/ so curved image sensors *are* already in the consumer area! However, there's a trivial technique which achieves almost the same result: place a plano-convex lens immediately in front of the flat image sensor. The extra thickness of glass in the center makes the middle of the sensor seem farther away, but because it is so close to the image plane, it doesn't do much to change the magnification and so on. This is a well-known technique, often used. John Savard |
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A curved image sensor
On Thursday, July 13, 2017 at 3:12:30 PM UTC-4, Quadibloc wrote:
On Thursday, July 13, 2017 at 1:08:08 PM UTC-6, Quadibloc wrote: On Wednesday, July 12, 2017 at 9:41:01 PM UTC-6, Quadibloc wrote: Of course, perhaps eventually inexpensive manufacturing techniques will be found, such as SOI where the insulating substrate can be heated enough to make it malleable without disturbing the delicate microcircuitry on its surface. An even more sensible method: Do SOI, but have the insulator already in a curved shape before starting. The optics for going from the mask to the substrate, after all, can *also* be designed to have curvature of field! And then there are no problems with deformation at all. Of course, that requires an investment in a very specialized production line. SONY bent their sensor after the fact, as this article notes - https://www.engadget.com/2014/07/08/...curved-sensor/ so curved image sensors *are* already in the consumer area! However, there's a trivial technique which achieves almost the same result: place a plano-convex lens immediately in front of the flat image sensor. The extra thickness of glass in the center makes the middle of the sensor seem farther away, but because it is so close to the image plane, it doesn't do much to change the magnification and so on. This is a well-known technique, often used. John Savard It's not a trivial technique. Using a fiield flattened introduces several problems. It increases the angle of incidence of the principal ray at the image plane. This reduces both MTF and image illumination. www.richardfisher.com |
#7
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A curved image sensor
On Thursday, July 13, 2017 at 9:38:43 PM UTC-4, Helpful person wrote:
On Thursday, July 13, 2017 at 3:12:30 PM UTC-4, Quadibloc wrote: On Thursday, July 13, 2017 at 1:08:08 PM UTC-6, Quadibloc wrote: On Wednesday, July 12, 2017 at 9:41:01 PM UTC-6, Quadibloc wrote: Of course, perhaps eventually inexpensive manufacturing techniques will be found, such as SOI where the insulating substrate can be heated enough to make it malleable without disturbing the delicate microcircuitry on its surface. An even more sensible method: Do SOI, but have the insulator already in a curved shape before starting. The optics for going from the mask to the substrate, after all, can *also* be designed to have curvature of field! And then there are no problems with deformation at all. Of course, that requires an investment in a very specialized production line. SONY bent their sensor after the fact, as this article notes - https://www.engadget.com/2014/07/08/...curved-sensor/ so curved image sensors *are* already in the consumer area! However, there's a trivial technique which achieves almost the same result: place a plano-convex lens immediately in front of the flat image sensor.. The extra thickness of glass in the center makes the middle of the sensor seem farther away, but because it is so close to the image plane, it doesn't do much to change the magnification and so on. This is a well-known technique, often used. John Savard It's not a trivial technique. Using a fiield flattened introduces several problems. It increases the angle of incidence of the principal ray at the image plane. This reduces both MTF and image illumination. www.richardfisher.com The whole idea behind improving digital imaging was concentricity of rays, so they avoided hitting the "walls" of the pixels of the sensor. So, you have to deal with micro lenses on the sensors on top of each pixel and how light interacts with them. Obviously, film grains never had this issue. |
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A curved image sensor
On Sat, 15 Jul 2017 01:34:25 -0700 (PDT), RichA
wrote: The whole idea behind improving digital imaging was concentricity of rays, so they avoided hitting the "walls" of the pixels of the sensor. So, you have to deal with micro lenses on the sensors on top of each pixel and how light interacts with them. Obviously, film grains never had this issue. The main reason for microlenses on the top of sensors is to allow a larger collection area with smaller underlying pixels- necessary because so many chip architectures require structure on the top surface that blocks part of the photosensitive area. |
#9
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A curved image sensor
Correct. However, micro lens arrays are only good with limited NA/principal ray angles otherwise light spills over from one pixel to the next.
http:www.richardfisher.com |
#10
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A curved image sensor
On Sat, 15 Jul 2017 06:22:48 -0700 (PDT), Helpful person
wrote: Correct. However, micro lens arrays are only good with limited NA/principal ray angles otherwise light spills over from one pixel to the next. And it's common for the lens arrays on sensors to add artifacts. It's not usually a problem for ordinary photography, but it can be a significant problem with astronomical imaging, even with the typically smaller principal ray angles from most telescopes compared with most camera lenses. |
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