Talk:Charge-coupled device

message: I've gotta second the technicality tag here.  I got to this article from the main page, but i have absolutely no idea what it's saying, and i'm fairly well versed in electronics, for a non-professional.
Archtemplar (talk) 17:03, 6 October 2009 (UTC)
replies: text: can you elaborate on the particular section(s)? User A1 (talk) 23:16, 6 October 2009 (UTC)
replies: text:  OK, having read it with your comment in mind, I now see what you mean. I will fiddle with this in about 9 hrs. If you have any more sections that you think are inaccessible, just jot them down here.  User A1 (talk)
the entire 'history' section is absolutely not wikipedia style at all.. definatly needs reworking. you'll understand what i mean after just merely skimming through. inspy 
Thanks A1, i think i understand its purpose better now.  It says, though, "for example conversion into a digital value"...it does other things too?
Archtemplar (talk) 18:02, 8 October 2009 (UTC)

text: Yeah, Bubble memory for one. Here you are, instead of using an Analog to Digital Converter, you are using a simple 0-1 conversion. Theoretically it could be used to do anything where you need charges moved around -- you could even use it to do weird things, like store an audio signal in an analog manner for later output (without digital conversion). It would work, but it would be very odd AFAIK. User A1 (talk) 23:20, 8 October 2009 (UTC)
thread_title: Technicality

message: Alison Chaiken 17:00, 26 September 2005 (UTC)
thread_title:  Add circuit diagram? 

message: I was interested in your comment:
"An interesting astronomical application is to use a CCD to make a fixed telescope behave like a tracking telescope and follow the motion of the sky."
I've not heard of this application before, do you have any further details or links?
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The context I've heard about it is: take a bunch of frames of the moving target with relatively fast shutter speeds and align them based on some common bright objects in all of the frames and then use a stacking algorithm. Stacking is not as effective as long exposures though.
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Stacking has other advantages. By taking a large number of frames and selecting only the best to stack, one can avoid the image degradation of atmospheric seeing or other transient factors inherent in long exposures.Wschart 01:50, 17 June 2006 (UTC)
thread_title:  CCD's in Non-Tracking Telescopes 

message: PizzaPuzzle, I am a little puzzled by the statement "CCDs commonly respond to 70% of the light to which they are exposed", because I'm not sure what the 70% is a measurement of.  Is it the percentage of the CCD surface that is covered by sensing material, as opposed to inert structures such as metal conductors?  Or is it the percentage of the incident energy in the visible spectrum that falls on the sensors that is converted to electric charge, instead of being reflected or absorbed as heat?  Or is it the product of both of these?  I would be grateful for clarification. -- Heron
: The latter, 70% of the photons react with the CCD - the rest are "wasted". As opposed to only 2% usage by a photographic plate. It would probably be useful to divide this page into astronomical CCD use, and more general/technical aspects. Pizza Puzzle
Thanks.  I added your 2% figure to the article, and moved the section to "Applications" to avoid repetition.  Perhaps only the general/technical aspects should be described here, with the applications (astronomical and otherwise) moved to digital photography.  What do you think? -- Heron
Why does light cause an accumulation of charge? Omegatron
You have to know a minimal bit of quantum physics for that. When a photon strikes an atom, it can elevate an electron to a higher energy level. CCDs are commonly made of negatively-doped silicon with many electrons - when light strikes them, it frees electrons to move around and they accumulate in the capacitors (I believe these are also called "wells.") Those electrons are shifted along the CCD and "counted" by a capacitor, giving an effective black & white image of how much light has fallen on each individual pixel.
Several things can affect whether a photon releases an electron: polysilicon circuits on the front-illuminated CCD surface can block light from entering, certain depths of the CCD may be penetrated by longer wavelengths without interaction with the atoms, certain screens may reflect off or absorb some wavelengths of the light, etc. (Thus BOTH of Heron's interpretations above are accurate.) Some wavelengths of light can free more or less than one electron per photon.
Knowing how many of the photons which fall on the CCD will release an electron is an accurate measurement of the CCD's sensitivity. This figure is called "quantum efficiency." Some CCDs can be made to reach as high as 95% QE. Several Japanese companies have developed many methods of increasing the sensitivity of the CCDs. For example, illuminating the CCD from the side without circuits, increasing the area of the CCD which is receptive to light.
Socrates's Universal Disclaimer: I don't know anything about anything. - Nocturnal
[edit:] Correction: the doped layers have spare electrons, but if they were free from the start that would of course defeat the purpose of the CCD! Sorry, I'm not a physicist, just an amateur photographer.
Frigoris 12:06, 5 April 2006 (UTC)
thread_title:  Basis of 70% 

message: We certainly need a few diagrams here. The architecture is also not very clear from the text alone. Those who can, please do. JMK 19:20, 30 April 2006 (UTC)
thread_title:  Achitecture 

message: I renamed this section CCD Vendors because that's all it was.  "External Links" is an invitation to linkspam.  Next, I suggest changing the external links to Wikilinks.  If a company is on this list, it should be noteworth and have it's own page.  Otherwise, it should be removed from the list.  Jehochman (Talk/Contrib) 02:21, 2 May 2006 (UTC)
replies: text: I removed the Vendors section.  Wikipedia is an encyclopedia, not the Yellow Pages.  There are plenty of resources for anyone who wants to buy such a device, starting with Google.  This was just spam. --Kbh3rdtalk 04:15, 14 June 2006 (UTC)
thread_title:  External Links 

message: Can someone please say something about sensitivity (I read something that about 8 photons are necessary to
stimulate a CCD while 70 are neccessary to "switch" a grain of photo-sensitive chemical in a film) as well
as the bandwidth of sensitivity of a "normal" CCD (in nanometer wave length). THANKS -- Michael Janich 09:23, 6 June 2006 (UTC)
thread_title:  Sensitivity and bandwidth 

message: Can someone explain the meaning of the measurements given for CCD size by camera manufacturers?  For example, what is 1/2.5" vs. 1/1.7"??  Originally, I thought these were shorthand inversions of inches (ie 1/2.5" = 0.4 inch diagonal), but it doesn't seem to work out correctly.  Thanks!  Slowmover 15:39, 6 June 2006 (UTC)
thread_title:  Camera specifications 

message: I added the technical template to the top of this page.  I've had small electronics courses and I had trouble understanding the article--I can't imagine what it would be like for a layperson.  Certainly more context, preferably less jargon, etc.  I don't know enough to do it myself, though.  Thanks to anyone who can help!  71.57.91.231 08:20, 16 November 2006 (UTC)
thread_title:  Technical Details 

message: The article claims that astronomical CCDs are cooled because of their infrared sensitivity to the emission of blackbody radiation from room-temperature sources.  This is not true.  CCDs are cooled because of the "dark" current produced by stimulation of electrons into the conduction band by thermal excitation from the temperature of the CCD itself.  Astronomical CCDs, and perhaps all CCDs, are not sensitive to the wavelengths where the blackbody peaks for room-temperature (around 10 microns or so). AmberRobot 19:08, 31 January 2007 (UTC)
thread_title:  Cooling of CCDs 

message: I find these two paragraphs (cable and ring electrodes stuff) incredibly confusing and they don't make any sense to me at all, despite reading them ten times and having studied a very fair deal of semiconductor physics as well as electronics. Shouldn't they be deleted or rewritten? The guy who made the edits (Arnero) seems like a real contributing user but as i said this makes absolutely no sense.
Grapetonix 20:50, 4 July 2007 (UTC)
thread_title:  Physics of operation, first two paragraphs 

message: Hello, I was just look at "http://www.tpromo2.com/ssmag/cctv/cctv3.htm" where it says that frame transfer CCD's are much less sensitive to infrared light than are interline transfer CCD's. This article says the exact opposite??? 65.183.135.231 (talk) 14:33, 23 May 2008 (UTC)
thread_title:  Interline transfer LESS sensitive to IR than frame transfer? 

message: If you look at the the wikipedia article Four Thirds System it says the sensor size is 18×13.5 mm (22.5 mm diagonal), with an imaging area of 17.3×13.0 mm (21.6 mm diagonal), while the table here says it 22.500×18.000 mm (28.814 mm diagonal). What is the actual number? The one here seems to be wrong.  —Preceding unsigned comment added by 74.64.99.12 (talk) 01:28, 19 June 2008 (UTC)
thread_title:  4/3" sensor size wrong? 

message: Can someone please add a Scanners section, describing how CCDs are used in optical scanners?
In particular, please could someone who is qualified explain the difference between a "3-line CCD (R,G,B)" and an "Alternative 6 line CCD" that you see are used in various models of scanner? Which one produces better quality images?
81.141.52.169 (talk) 09:51, 20 July 2008 (UTC)
thread_title:  Use of CCDs in scanners 

message: I think that the article should mention CCD blooming. What do you think? --pabouk (talk) 12:51, 10 October 2008 (UTC)
replies: text: Sure -- Be bold and add it, if you have the time! User A1 (talk) 08:47, 11 October 2008 (UTC)

text: I edited it a bit, as it didn't agree with what I know about anti-blooming structures.  Dicklyon (talk) 04:30, 6 June 2012 (UTC)
thread_title:  CCD blooming 

message: There is no discussion of gain in the article.  —Preceding unsigned comment added by Lzkelley (talk • contribs) 07:44, 13 November 2008 (UTC)
thread_title:  Gain 

message: There is an issue brewing with regard to the completeness of credit to those behind the work for which Smith and Boyle are being honored with a Nobel Prize in Physics. According to the Institute of Electrical and Electronics Engineers (IEEE) Spectrum, as available on http://spectrum.ieee.org/podcast/semiconductors/devices/who-deserves-credit-for-the-nobelprizewinning-ccd, Michael F. Tompsett and Eugene Gordon, also then at Bell Labs, may have had a signficant hand in the work. There is a series of links provided, in chronological order, all within the IEEE site.
I lack sufficient experience in Wikipedia to know how best to proceed. Thanks!
Dhugot (talk) 14:33, 15 October 2009 (UTC)
thread_title:  Provenance and the Nobel Prize 

message: Both are fine to use, there is no argument there. However, since the rest of the article uses American English not British English, (based on the spelling of color), the use of aluminium is inconsistent. Consequently, I am changing it to aluminum.The Lamb of God (talk) 02:45, 23 January 2010 (UTC)
thread_title:  Aluminum vs Aluminium 

message: Not that it actually matters, but isn't the Media Wikiproject a very long way from getting to *this* article?  One might as well include "rechargeable batteries" in media, after all, journalists use rechargeable batteries...or "leather" because they wear shoes....or "tomatoes" because journalists often eat pizza. I've taken the liberty of removing that tag.  --Wtshymanski (talk) 21:39, 13 September 2010 (UTC)
thread_title: Media?

message: What the basics of operations section needs is a description of how the photoactive silicon layer works.  Or a link to a description of how it works, but I couldn't find one.  — Preceding unsigned comment added by 74.38.239.72 (talk) 14:53, 22 August 2011 (UTC)
replies: text: See if the edit that I just made is helpful for that.  Dicklyon (talk) 01:08, 23 August 2011 (UTC)
replies: text: I have changed your edit, because CCDs use MOS capacitors to do the job done by p-n junctions in photodiodes. But the article still lacks a device physics perspective on the generation of electron charges. I'll give it a try based on Sze's Device physics. Mathieu Perrin (talk) 16:12, 26 November 2011 (UTC)
thread_title:  the photoactive layer 

message: I just reverted the change of "intensity" to "irradiance" in "causing each capacitor to accumulate an electric charge proportional to the light intensity at that location."  I can agree that intensity of is not very specific, but "proportional" can hide all times of factors, like the integration time and spectral weighting.  However, "irradiance" is probably too specific, as it suggests equal weight for all wavelengths, which would certainly not be accurate (not even to first order); it would be no more correct than "illuminance", which is wrong in the same way, even though it is commonly used, in the measurement "lux-seconds".  Getting into more detail makes sense only if we have something that's correct and sourced.  Dicklyon (talk) 20:38, 17 October 2011 (UTC)
thread_title: intensity vs. irradiance

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thread_title: File:Frame Transfer CCD.jpg Nominated for speedy Deletion

message: Can you imagine a non-IC CCD?  Picture rows upon rows of 6SN7s glowing away...it would be like a vacuum-tube CD player or cell phone. --Wtshymanski (talk) 14:23, 9 March 2012 (UTC)
replies: text: And the relevance of this piece of trite to improving the article is what exactly? DieSwartzPunkt (talk) 13:20, 6 December 2012 (UTC)
thread_title: Microelectronic

message: The 4th line below the heading "Design and manufacturing" contains the string "Sze".  Is this a typo?  If not, please explain it.
I think this article is NOT confusing at all, though I, too, would like to see a little more physics.
Tim Coahran (talk) 02:12, 21 March 2012 (UTC)
replies: text: It's Dr. Sze's last name; not a typo.  Dicklyon (talk) 02:44, 21 March 2012 (UTC)
thread_title: Sze

message: "In applications with less exacting quality demands, such as consumer and professional digital cameras, active pixel sensors (CMOS) are generally used; the large quality advantage CCDs enjoyed early on has narrowed over time."
Um, no. In video at least, CCDs are still generally preferred to CMOS sensors, partly because CCDs use intra-frame compression, while CMOS chips use inter-frame. The practical consequence is that some CMOS camera moves can produce flutter that is easily visible onscreen.Jim Stinson (talk) 18:29, 22 May 2014 (UTC)
replies: text: For scientific instruments (read satellite telescopes) CCD's are still the preferred camera. A lot of high end cameras have post processing to deal with stuff like flutter. CombatWombat42 (talk) 20:47, 22 May 2014 (UTC)
thread_title:  CMOS VS CCD 

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thread_title:  External links modified 

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message: The giant formula given for EMCCD counts is wrong. In fact, it is nutty. If the gain is g=1, then P(n|m) = kronecker_delta(n,m). The formula fails the simplest possible sanity check.
2600:1700:C280:1CF0:69FB:6EAF:DFA5:32FB (talk) 21:31, 10 February 2021 (UTC)
thread_title:  EMCCD Formula Wrong