Re: Vertical capacitors for image sensors

On Tue, 6 Jun 2006 22:47:52 +0200, Alfred Molon wrote:

I was thinking of a "greek pi" structure with a light sensitive area
above (the horizontal line of the pi) and a vertical capacitor below
(the two vertical lines of pi).

And I was thinking that your geometry probably doesn't work for
sensors. My guess (since I haven't studied sensors) is that the
light sensitive area would have to be one of the capacitor's two
plates. That is, one (but not both) of your two vertical lines,
which in your design would be hidden from the incoming photons,
which would strike not the broad side of one plate, but the thin
edge of both plates as well as the thin dielectric separating them.

To continue with the guesses, the way the sensor might work is
that when photons strike one of the two plates, a voltage potential
between the two plates is created, and the capacitance is used to
preserve the voltage long enough for the camera to read it. To
increase the dynamic range you'd have to increase the number of
photons that could be collected, and that would be proportional to
the capacitance. There are several ways the capacitance could be
increased. One is to increase the plate's surface area, and one
way that is done is to replace a tiny P&S sensor with a larger
sensor, such as a 24mm x 36mm FF sensor. The other way would be to
place the two plates closer together, but current sensor technology
may already be too close to the mechanical or quantum limits to make
any further capacitance increases practical. There are probably a
couple of people here that have a better understanding of how
sensors operate and are fabricated, so whether they concur or
disagree with me and thee, we'll have to wait and see. :)

.

Relevant Pages

  • Re: Precision Electronic Levels - The Germans Arrive
    ... on capacitance so if the pendulum leans to one side, ... capacitance sensor for tracking of the movements of small animals in ... A simple display would use the rotor angle ... How big are these rotors, what are they made of, and how fast do they ...
    (rec.crafts.metalworking)
  • Re: Precision Electronic Levels - The Germans Arrive
    ... elektronischen Einachspendelsystem HRTM" by Timo Kahlmann (ETH Zurich), ... on capacitance so if the pendulum leans to one side, ... capacitance sensor for tracking of the movements of small animals in ...
    (rec.crafts.metalworking)
  • Re: Precision Electronic Levels - The Germans Arrive
    ... traditional transformer capacitance bridge with synchronous detector, ... capacitance sensor for tracking of the movements of small animals in ... A simple display would use the rotor angle ... How big are these rotors, what are they made of, and how fast do they ...
    (rec.crafts.metalworking)
  • Re: Free Electricity !
    ... essential components - a material with a high capacitance which stores ... the charge, and a material with a very high resistence that keeps the ... The way I had thought of it is that the charged plates exert ...
    (uk.legal)
  • Re: Is there an electronics design newsgroup?
    ... John Larkin wrote: ... The capacitance of widely-separated electrodes is asymptotic to the ... on widely-separated circular plates. ...
    (sci.electronics.design)