Canon Patent to reduce image noise generated by the magnetic field of image stabilisation unit

Canon Patent

Well, this is an interesting Canon patent application we spotted (20180164603), and it shows how much care Canon applies to details.

Some background information first. Simplifying it very much, the image stabilisation system of a lens is build on top of a vibration gyroscope sensor. The process of stabilising an image in the lens occurs through a image (shake) correcting unit. The correcting unit uses electromagnetic fields, generated by applying current to a coil.

The generated electromagnetic fields can influence the electronic circuitry and hence may degrade the image quality by generating noise in the image. Turns out that shielding the coil isn’t that easy.

If I got the patent right, it tries to reduce the magnetic field by clever use of non-magnetically conductive materials and shielding. From the patent literature:

According to one aspect of the present invention, there is provided an imaging lens including: a lens; an image shake correcting action unit provided movably in a direction perpendicular to an optical axis of the lens; a stationary unit for supporting the image shake correcting action unit; a permanent magnet provided on one of the image shake correcting action unit and the stationary unit and a coil provided on an other; a drive circuit for moving the image shake correcting action unit relative to the stationary unit; a mount section for being connected to an imaging unit having an imaging element; and a conductive member which is nonmagnetically conductive and disposed between the coil and the mount section so as to include a facing surface facing a surface formed by a binding wire of the coil and having a larger area than a surface formed by an inner periphery of the coil.

This patent application might go into production one day.

Other Canon patent applications we think might get into production in the next few years are these:

Canon Patent Application to combine Air Sphere and Flourine Coating

Canon Patent Application

Canon patent application US20180148603 discusses how to combine Air Sphere coating with Fluorine coating to further reduce optical artefacts like flare and ghosting. Both techniques are already used in Canon lenses (see video below), though I can’t say if they are used in combination.

From the patent literature.:

A low-refractive-index layer utilizing gaps between particles has a problem that oily matter penetrates and diffuses into voids between particles in the film. The present inventor has found that the contamination that has not been visually recognized at the time of adhesion of the contamination and low-molecular-weight oily matter generated by the adhesion of contaminants diffuse among particles in the low-refractive-index layer to decrease the refractive index, resulting in deterioration in the appearance to a degree that can be visually recognized.

Canon Patent Application for 800mm f/5.6 lens

Canon Patent Application

A Canon patent application (2018-087965) for what might be the future replacement for the Canon EF 800mm f/5.6L IS lens.

The patent literature describes a lens concept where weight and size are reduced without affecting optical performance or causing increased chromatic aberrations.

Machine translated patent literature excerpt:

The method of using for a part of imaging optical system the diffracted-light faculty which has a diffraction working effect as a method of reducing lens weight is known correcting satisfactorily several aberration including the chromatic aberration of the imaging optical system. The imaging optical system which constituted the front lens group from ** material whose refractive index is higher than a low dispersing material with abnormal portion dispersibility, such as fluorite, and attained size and weight reduction of the whole system is known, using a diffraction working effect and reducing the lens number of sheets of the front lens group which was conventionally required for aberration compensation

There is a lot of buzz around Canon patent applications as of lately, and a lot of misunderstanding too. Bear in mind that a patent application does not mean a company will launch a product anytime soon. A patent application is a way companies have to secure their research and their intellectual property. In this sense, nothing here is a guarantee that the EF 800mm f/5.6L lens will be replaced in the close future.

Some Canon patent applications we think might get into production in the next few years are these:

Canon Patent Application for a 11-440mm f/2.1-4.1 Cinema Zoom lens

Canon Patent Application

Canon patent application (US 20180143412) for what looks like a 11-440mm f/2.1-4.1 Cinema Zoom lens.

From the patent literature:

Conventionally, four-unit zoom lenses are often used as zoom lenses for television cameras because it is relatively easy to achieve a wide angle of view, a high zoom ratio, and size and weight reduction. Such a four-unit zoom lens includes, in order from the object side, a first lens unit having a positive refractive power that does not move for zooming, a second lens unit having a negative refractive power that moves during zooming, a third lens unit for correcting variation in the image plane caused by zooming, and a fourth lens unit having a positive refractive power for imaging.

In recent years, there have been proposed zoom lenses for television cameras including three, four, or more movable units as zooming units with functions as a variator and a compensator.

[…]

Thus, the present invention has an objective to provide a zoom lens including three or more movable units as its zooming units and simultaneously achieving a wide angle of view, a high zooming ratio, size and weight reduction, and particularly high performance in the focal length range from the wide-angle end to the zoom middle position. The present invention also aims to provide an image pickup apparatus having such a zoom lens.

To attain the above objective, a zoom lens according to the present invention includes, in order from an object side to an image side, a first lens unit having a positive refractive power that does not move for zooming, a second lens unit having a negative refractive power that moves during zooming, a third lens unit having a negative refractive power that moves during zooming, a fourth lens unit having a negative refractive power that moves during zooming, and a relay lens unit having a positive refractive power and being located closest to the image side that does not move for zooming. The second lens unit moves to the image side from a wide-angle end to a telephoto end. When a focal length fx determined based on a focal length fw of the zoom lens at the wide-angle end and a zoom ratio Z is fx=fw×Z0.38, the zoom lens satisfies 0.05<L2min/L2w<0.98, where L2min is a minimum distance between the second lens unit and the third lens unit in a zoom range from the wide-angle end to the focal length fx, and L2w is a distance between the second lens unit and the third lens unit at the wide-angle end.

Patent literature is a hard reading. If I got it wrong or if you have additional intel, please feel free to sound off in the comment section.

canon patent application

Canon Patent Application for a new mount type (but it doesn’t mean Canon’s FF MILC will feature it)

Canon Patent Application

EDIT: it appears to be an EF mount with high speed electrical connections, not a hybrid mount, not a new mount type.

Hi Lows Note spotted a Canon patent application (2018-084713) for a mount type that can manage different types of lenses. It appears to be neither and EF nor an EF-M mount (but we are not really sure about that).

From the patent literature (machine translated):

Conventionally, the serial communication (synchronous serial communication) of a clock synchronization system has been adopted as a communication method of a camera and an interchangeable lens. The following technical contents are disclosed in the Patent document 1. First, synchronous serial communication is performed with the first communication speed with which an interchangeable lens old type can also communicate. When the interchangeable lens with which it is equipped is distinguished from a new lens by the communication content, it changes to the synchronous serial communication in a more nearly high-speed second communication speed.

What we understand from the patent literature is that the mount type can handle two different types of lenses (old type vs. not old type). This has led some people to speculate about a hybrid mount type that has to come with Canon’s future full frame mirrorless camera.

As cool as this would be, there is absolutely nothing in the patent literature that makes us think Canon will feature a hybrid mount type that will fit all of their lenses (with different mounts), and possibly even more.

In the image on top you can see an element (1D) that has the purpose to detect newer lenses, i.e. lenses with a more recent AF technology and interface protocol. The two kind of lenses referenced in the patent literature and in the excerpt above, are most likely lenses with an older AF interface protocol, and newer lenses with faster AF speed and an updated interface protocol.

Canon patent application: wide-angle zoom lens for full-frame mirrorless camera

Canon Patent

Canon patent application 2018-77320A describes a 16-28mm f/2.8, wide-angle zoon lens for a full frame mirrorless camera.

  • Zoom ratio: 1.67
  • Focal length: 16.48 – 27.44mm
  • F number: 2.88
  • Half angle: 52.70 – 38.25
  • Image height: 21.64mm
  • Back focus: 12.33 – 10.00mm

We expect Canon to announce their full frame mirrorless camera within the next 8 to 12 months. For the latest about it see here.

More Canon patent applications are listed here.

[via Hi Lows Note]