Nikon patent combines dedicated AF and imaging sensors

Nikon dedicated AF and imaging sensor patent
Nikon dedicated AF and imaging sensor patent 2

Nikon patent application 20130182173 is for combining/stacking a dedicated AF and imaging sensors without losing any light (in theory):

"The idea is simple: RGB color filter array does not use roughly 2/3 of the light in each pixel, why not use the lost light by a complementary-colored organic AF sensor stacked on top on the regular Bayer-pattern sensor."

From the patent application:

"A solid-state imaging device includes a second image sensor having an organic photoelectric conversion film transmitting a specific light, and a first image sensor which is stacked in layers on a same semiconductor substrate as that of the second image sensor and which receives the specific light having transmitted the second image sensor, in which a pixel for focus detection is provided in the second image sensor or the first image sensor. Therefore, an AF method can be realized independently of a pixel for imaging."

Via Image-sensors-world

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  • A.B Photography

    …I don’t understand a word, so it must be good…shut up and take my money!

    • Calibrator

      Venture capital at work, folks!

    • MJr

      It says “The idea is simple: …” so how can that be ? 😛

      • krikman

        “The idea is simple: …” means that they still don’t know how to realise it and ever not try.

      • krikman

        “The idea is simple: …” means that they still don’t know how to realise it and ever not try.


      it’s simple, use the lost light for Auto-focus system as a second layer over the sensor, or Under and use the organic sensor (like the Foveon) as the prime sensor.

  • Herr_Synnberg

    One sensor is RGB while the other is CMY. Interesting….

    • soap

      Since one is an additive colorspace and the other is its complementary subtractive colorspace…

      Do you see where this is going…

      • Scott

        I haven’t a clue but I’m curious! 😀

  • o

    Reading this triggered my ADD

  • Maertyn

    Sounds great
    Put it in the D400 😉

    • NRA Advocate

      D400 is NOT coming.

      • Matthew Fleisher


  • Sebastian

    it can’t be that simple, because if it were, why not just stack THREE of these complementary pixels on top of each other and have single-pixel color detection. Like the Foveon sensor, but with sharp transitions between the three colors. The trick is in stacking the pixels.This is where the organic film must come in. Still, the question is, why is AF the thing being patented here? Is the obvious use for this additional layer, which is to increase effective quantum efficiency by collecting the complementary color, already patented?

    • lefantome

      Maybe that’s because it’s difficult to cope with the three layers? I’ve not used a Foveon sensor before but some of my friends say that the Foveon sensor has color cast issues and the high ISO performance is not as good…

      • Calibrator

        > but some of my friends say that the Foveon sensor has color cast issues and the high ISO performance is not as good…

        It’s well reported that current Foveon sensors are all crap at higher ISO (“higher” = anything over 400), compared to traditional sensors, Bayer or not.

    • Dpablo unfiltered

      Probably the quality of the light is not as important for the secondary use.

      • Sebastian

        The quality?

        • Evan Richardson

          Yeah man quality light. In 3rd world countries, they only get poor quality light, while in 1st world countries you get much higher quality, distilled light. You can buy better quality light for a price though.

    • FredBear

      Because one can’t get ‘absolute’ cut off between the light (colour)absorbance of each layer – in other words one gets a Gaussian absorbance curve, not a series of absorbance ‘blocks’.

  • Drq999

    This is a death sentence to DSLR, only mirrorless in the future!

    • Spy Black

      I don’t see what’s so great about a modern optical finder, personally. I might miss optical finders if I could effectively use my manual focus lenses with them, but modern bodies have a crappy.7x magnification that makes it difficult. I have no problems manually focusing on the groundglass of my F and F2 bodies (without the focusing aids), but at 50mm and below it’s nearly impossible with my D600 and D5100 bodies. Even with a KatzEye screen in the D5100 it’s extremely difficult.

      A mirrorless design might actually make it easier for me to manually focus with my manual focus lenses, so I would welcome that.

      • Calibrator

        Some of the new mirrorless system have focussing aids that are much more advanced. Not only “focus peeking” but also “focus zone display” where you get an idea from where to where the image is in focus.
        That’s great for anything from macro to landscape and anything in between (no pun intended ;-)).
        Low-light photography is also something an EVF comes in handy. It’s a noisy image, for sure, but it’s much more usable than an OVF in that situation.

        And then there is stuff like “exposure preview” where the image in the EVF (or on the LCD) is updated while in bulb mode so you can end it when you feel the image is right.

        However, I’m disappointed how small the image in some EVFs appear to my eyes compared to the OVF of my D7000, which is comparatively big & bright for an APS-C DSLR.

        It’s clearm though, that the industry is getting rid of the mirrors – and the needed costly mechanics (both parts & assembly time).

        I don’t know how much time Nikon will need (or rather how much time they will take) for their switch but the days of the mirror are numbered.

      • hectorcorderoe

        the dk-21m worked for me on the d5100. there`s slight distorsion but its just the finder, not the photo. hope it helps.

        • Spy Black

          Yeah, I tried that. Slight improvement. Some vignetting tho. Looks like the Zack Morris version of eyepieces too.

          I just don’t understand why we have to deal with .7x magnification in the first place. It’s utterly annoying. Will need a custom eyepiece.

      • Scott

        I do a ton of manual focus 50mm f1.4 @ 1.4 with my D5100 but all of it is through live view. You have to deal with the slight shutter lag and I know some photographers are totally against using the screen while shooting but it works far better then the viewfinder.

        I’ve actually cut down an old focusing screen to put in the camera but never did it cause it will have to be fine tuned with shims as far as I understand and I’m lazy LOL.

        I so wish the Nikons had focus peaking in live view.

        • Spy Black

          Manual focusing through live view is impractical when A) you’re outdoors in daytime and/or B) you’re hand holding the camera. Overall it’s a very awkward way to focus, even indoors on a tripod. Just make the damn eyepieces 1x and be done with it. Problem solved.

          • Scott

            Can they with crop cameras though? I’m not to familiar with the design aspect of the pentax box and such obviously.

            It’s true that outside it’s not ideal. I don’t often shoot outside midday though, in the evenings and mornings it works fine.

            I use it hand held for indoor music photography AL THE TIME. You just have to prefocus more, anticipate movement and be ready to bin duds. Not ideal by any means but I can’t put out for a 50mm 1.4G at the moment LOL

            I actually like using live view and the often maligned fold out screen for music photography in small bars and such though cause I can get really low angles and interesting perspectives without crawling around on my back as I would while using the viewfinder.

            I’m going to miss that fold out function if I move up in the lineup.

            • Spy Black

              “Can they with crop cameras though?”

              Sure can. Oddly the D7100 has a .94x viewfinder eyepiece. At this point I’d be happy with that on my D600!

    • Mike

      Not necessarily. AF on sensor could mean better AF in movie mode on DSLRs i.e. Canon 70D. Personally, I hope OVF sticks around for a while… technically, what you see in an EVF already happened, so you missed it. That, Fuji’s implementation of both is slick plus the info overlay on an OVF is even sweeter…. real time histogram…

  • dilbert

    Use from RGB the R+G for focussing when you want only B for measurement is pretty clever.

    One might add the signals and have a all R+G+B=grey value, too.

    Maybe even using CMY for dark colours and RGB for bright.

    Soo many options, one has to wonder why they did not do that earlier. Then again: how much transmission might this CMY-layer allow? Worse than the filters today I’d guess.

    Let’s see. darn good invention anyway, bravo Nikon!

    • Marco Santa Cruz

      not nikon… just a chump trying to make ends meet, trying to put food on the table who had no other choice than to join the rat race in a moment of desperation… but i know what you meant when you said that… just thought i’d say this though

  • Eric Calabos

    “since an organic photoelectric conversion film is used instead of a color filter required for the conventional single plate type image sensor, the incoming light, which would have been otherwise absorbed by the color filter, can be effectively utilized by the second image sensor


    the output signal of the second image sensor may be utilized not only for focus detection but also for white balance control”


  • Alan


  • Syco

    So what its saying is – it’s an uber advanced nikon 1 sensor.

    Now on 35mm with a metering and subject sensor the same size as the images sensor, the amasing things todays’ 91K sensor does, imaging if it was 36MP – it could lock and track the eyeballs of a target based on facial recognition/lock skin tone and eye colour, through a crowd, never losing its subject (3d tracking actually works properly for once).

    No more mirrors – as long as there is no lag to the evf would be great.

    No limit to frame rate

    Silent shutter….

  • lorenzo

    maybe we can see a new D800/Es that doesn’t have the LT AF problem?

  • loui

    I don’t understand. If the “second” sensor(103 on the graph) is, let’s say magenta, how can the “first” sensor(102) output green? Sorry for my slowness.

    • j v

      If the photosite on sensor 102 measures the green, it means it does not need the wavelengths for red and blue (together: magenta); typically, they are filtered out and ignored.

      This patent uses the information that is currently ignored in sensor 103 for AF.
      It is a bit similar to the Foveon sensor, where the RGB are done in different layers. As that is patented (and has some low light performance issues), Nikon thought of using the info to feed an AF system.

      • loui

        Thanks! Now I understand. The magenta filter lets the green light pass.

        • j v

          I’m no expert at this… only thing is that as long as (in your example) the green is passed onto the photosite of sensor 102, it does not matter what happens to the wavelengths that don’t matter.

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