Canon Patent: Quad Pixel Phase Detection Auto-Focus

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Here is a new and definitely interesting Canon patent application: Quad Pixel Phase Detection AF. It’s not the first patent for this technology.

Canon patent application 2023166867 (Japan, published 11/22/2023) discusses methods and technology for Canon’s next generation autofocus technology, Quad Pixel Detection AF.

From the patent literature:

  • [Problem] To improve the performance of focus detection in focus detection using an image plane phase difference method that uses signals output from image sensors having different vertical and horizontal lengths.
  • TECHNICAL FIELD
    The present invention relates to an image sensor in which a pixel section having a plurality of photoelectric conversion sections is two-dimensionally arranged, and an image sensor equipped with the image sensor.
  • BACKGROUND ART
    Conventionally, as one of the focus detection methods performed in an imaging device, a pair of pupil division signals are acquired using focus detection pixels formed on an image sensor, and a focus detection method using a phase difference method is used. A so-called imaging plane phase difference method for performing detection is known.
  • As an example of such an imaging surface phase difference method, there is an imaging device using a two-dimensional imaging element in which one microlens and a plurality of divided photoelectric conversion sections are formed for one pixel. It is disclosed in Patent Document 1. The plurality of photoelectric conversion units are configured to receive light transmitted through different regions of the exit pupil of the imaging lens via one microlens, and perform pupil division. Then, by calculating the amount of image shift from the phase difference signal that is a signal of each photoelectric conversion unit, focus detection using a phase difference method can be performed. Further, by adding up the signals of the individual photoelectric conversion units for each pixel, a normal image signal can be obtained. Further, Patent Document 1 discloses a configuration in which the saturation resistance of the pixel is increased by arranging a plurality of types of pixels having different heights of separation barriers between photoelectric conversion parts in the pixel.
  • In such an image sensor, in a configuration in which a plurality of photoelectric conversion units are arranged horizontally within a pixel and the pupil division direction is horizontal, for example, when the subject has a horizontal striped pattern, parallax is This may be difficult to see, and focus detection accuracy may deteriorate.
  • On the other hand, Patent Document 2 discloses a technique for improving focus detection accuracy by providing two types of arrangement directions of photoelectric conversion units for each microlens and two types of pupil division directions. There is. Furthermore, Patent Document 2 discloses a structure that separates vertically adjacent photoelectric conversion units and a structure that separates horizontally adjacent photoelectric conversion units, and has a structure that allows electric charges to leak to adjacent photoelectric conversion units. It is disclosed that the With this structure, supersaturated charges received in excess of the amount of charge that can be accumulated by one photoelectric conversion section leak and accumulate in different photoelectric conversion sections arranged in a predetermined direction. Even in the case of saturation, horizontal or vertical phase difference focus detection is possible.
  • Most conventional image sensors do not have an aspect ratio of 1:1. Therefore, when focus detection pixels using the image plane phase difference method in the vertical direction and focus detection pixels in the horizontal direction are arranged on the image sensor, focus detection using the image plane phase difference method is difficult, especially in the periphery of the image sensor. Performance is biased towards either the vertical or horizontal direction.
  • The image sensor described in Patent Document 1 changes the separation state of the photoelectric conversion unit depending on the saturation state of the pixel. Therefore, depending on the aspect ratio of the image sensor, the state of charge crosstalk (a phenomenon in which charge leaks to the adjacent photoelectric conversion unit) between the photoelectric conversion units in the vertical focus detection pixels and the horizontal focus detection pixels respectively occurs. It is not possible to control the above problems and cannot solve the above problems.
  • Furthermore, the image sensor of Patent Document 2 does not have a configuration that controls charge crosstalk when the photoelectric conversion section is not saturated, and also controls charge crosstalk between the photoelectric conversion sections according to the aspect ratio of the image sensor. Since there is no mention of the talk rate, the above problem cannot be solved.
  • The present invention has been made in view of the above problems, and is intended to improve the performance of focus detection in focus detection using an image plane phase difference method that utilizes signals output from image sensors having different lengths and widths. The purpose is to

More Canon patent applications are listed here.

[via asobinet]

Canon Patent: AF-Motor With Reduced Size And Lower Power Consumption

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A new Canon Patent application.

Canon patent application 2023096628 (Japan, published 7/7/2023) discusses technology and methods for a autofocus-driving motor with reduced size and lower power consumption.

The motor described in the the patent literature is a “linear motor”. Canon interchangeable lenses have a “ring-type USM”-motor for single-lens reflex cameras and a “NanoUSM”-motor for mirrorless cameras. Both are driven by ultrasonic waves, so this would be a new kind of motor driving Canon lenses.

From the patent literature:

A linear motor, a lens barrel, and a driving device that can improve power efficiency while suppressing an increase in external size are provided. BACKGROUND ART A linear motor is a motor that mainly generates force in one direction

It is used in a wide range of industrial fields. Linear motors are often used exclusively in linear drive applications and are often used in combination with linear guide mechanisms. Linear motors are classified into electromagnetic, pressure, friction, and tension/extrusion types according to the principle of thrust generation, and into finite tracks, endless tracks, etc. according to the drive range. be. In addition, devices that use mechanisms such as so-called rack and pinions and tires to convert the thrust of a normal rotary motor into linear thrust are also broadly classified as linear motors (linear actuators).

An example of the use of a linear motor is a focusing mechanism in a lens barrel. In the lens barrel, the focus operation is performed by moving the focus lens group inside the lens barrel back and forth on the optical axis perpendicular to the camera’s image sensor in order to focus on the subject at the desired position when shooting. is done. A linear motor is used to adjust the movement of the focus lens group.

Necessary conditions for the linear motor used in the focus mechanism in the lens barrel are that it has a size that fits inside the lens barrel, and that the maximum output and resolution of the thrust force sufficient to move and adjust the focus lens group are required. Being prepared, being quiet, etc. To meet these conditions, among the above categories, electromagnetic linear motors with finite trajectories are used, especially voice coil motors (VCMs), which generate the Lorentz force through a combination of permanent magnets and coils. may occur.

Since the VCM does not generate thrust when it is not energized, when using the VCM as a focus mechanism in the lens barrel, it is necessary to always energize the VCM to hold the focus lens group during use. For this reason, depending on the shooting scene, it may consume a large amount of power and the battery of the camera will be consumed faster than when using other friction type ultrasonic motors for the focusing mechanism in the lens barrel. be. Therefore, when a VCM is used as a focusing mechanism in the lens barrel, it is required to improve the power efficiency of the VCM.

In order to improve the power efficiency of a VCM with a finite orbit without increasing the external size, the efficiency of a magnetic circuit composed of a permanent magnet and a yoke (hereinafter simply referred to as magnetic efficiency), that is, the coil area of ​​the VCM The key is how to increase the density of the magnetic flux that contributes to the generation of thrust. The magnetic circuit here is an expression that compares the flow of magnetic flux in space to the flow of current in a circuit, and indicates the direction and magnitude of the magnetic flux density at each point. itself is also shown. In addition, in general finite orbit VCM, it is known that the magnetic efficiency is relatively lower at both ends of the drive stroke than at the center, and it is important in practice to suppress this. (See, for example, Patent Document 1).

However, in the VCM of Patent Document 1, since the magnetic efficiency in the central portion of the driving stroke is reduced in order to equalize the magnetic efficiency in the driving stroke, there is a problem that the power efficiency as a whole deteriorates. In addition, since the configuration of Patent Document 2 requires a separate fixing means for fixing the magnet, there is a problem that the external size of the linear motor tends to increase.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide a linear motor, a lens barrel, and a driving device that can improve power efficiency while suppressing an increase in external size.

More Canon patent applications are listed here. Some particularly interesting patent applications we think might get into production are these:

[via asobinet]

Canon Patent: Shutter Button Vibrates When Focus Is Acquired

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And here is the third Canon patent application of today (see here and here), and this is a rather cool one in our opinion.

Canon patent application 2023009356 (Japan, published 1/20/2023) discusses methods to make a shutter button that vibrates when autofocus is locked. Pretty cool, isn’t it? Think of situations where silence is important, but getting to know when AF locks is too.

From the patent literature:

An optical device capable of increasing vibration transmitted to a release button with an inexpensive and compact configuration is provided.

Description of the Related Art

Conventional single-lens reflex cameras generate camera shooting sounds such as shutter sounds and mirror drive sounds when a release button is operated to take a picture. Thereby, the user can recognize by the sound that the camera has performed the photographing operation. However, in recent years, when photographing athletes, the sound of the camera being shot distracts them from their concentration. becoming a problem. As a countermeasure for this problem, mirrorless cameras have become popular and the driving sound of the mirror has been eliminated. For this reason, among mirrorless cameras, there is a silent shutter camera that significantly suppresses the camera shooting sound even when shooting in a quiet place by reducing the shutter sound.

However, since the silent shutter camera is almost silent, when the user operates the release button to take a picture, it is difficult to determine whether or not the image has been reliably recorded. In order to address this problem, a configuration has been disclosed in which the release button is vibrated so that only the user can perceive the shooting operation while suppressing the camera shooting sound.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an optical apparatus capable of increasing the vibration transmitted to the release button with an inexpensive and compact configuration.

More Canon patent applications are listed here.

[via asobinet]

Canon Patent: Eye Control Autofocus For Mirrorless Cameras

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A new Canon patent application about eye controlled autofocus. Two patent applications, to be precise.

Cannon patent application 20220247904 (US) refers to a bigger sized mirrorless camera (like the EOS R3) and Canon patent application 20220247933 (US) to a smaller one. Here is the abstract for the former patent application:

And the abstract for the latter patent application:

More Canon patent applications are listed here. Some particularly interesting patent applications we think might get into production are these:

[via NL]

Canon Australia Indeed Recalls “very small number” Of EOS R5 C Due To AF Issues

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Days ago a rumor came up suggesting Canon Australia is set to “halt sales of the Canon EOS R5 C“, without any apparent cause. Well, reality is a little less dramatic.

As Canon Australia itself revealed in a product advisory, a very small number of Canon EOS R5 C units is going to be recalled. The issue seems to be related to autofocus issues.

Customers who recently purchased the EOS R5 C digital cinema camera

18th March 2022

It has been discovered that the following minor defect may occur in some EOS R5 C digital cinema cameras. We sincerely apologise for any inconvenience and concern this may cause to customers using this product. We will continue to ensure thorough quality control so that customers can use this product with peace of mind.

Issue
Due to a manufacturing defect in the autofocus, the camera may repeatedly go in and out of focus in movie mode.

Products
Selected units in Australia of the EOS R5 C digital cinema camera.

Our action
We are aware that a very small number of units have been delivered to customers prior to this issue being identified. For those who received their unit on or before 21 March 2022, please contact the retailer you purchased the product from to organise the return and replacement or repair of your camera. We appreciate your understanding.

For those customers eagerly awaiting their EOS R5 C we expect this may delay shipping of your product.

So far it seems other markets than Australia are not affected by this.

Canon Technical Advisor Rudy Winston Explains Canon Auto Focus

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Here is a neat video. Host Rudy Winston, Canon technical advisor of renowned fame, explains how Auto Focus woorks on Canon cameras.

Join Rudy Winston, a Technical Advisor in the Product Planning Dept. for Canon USA, and me as we take a deep dive into the amazing auto-focus systems available in the current line of Canon cameras, on this Behind the Shot.

This is a rather exhaustive and long video, coming from Behind The Shot (you can follow Steve Brazill on Twitter). So here is the table of contents:

  • 0:00:00 – Intro
  • 0:01:26 – Interview with Rudy Winston
  • 0:12:56 – General AF Questions
  • 0:18:40 – Canon R5 AF Menu Page 1
  • 0:41:27 – Canon R5 AF Menu Page 2
  • 0:45:41 – Canon R5 AF Menu Page 3
  • 0:57:36 – Canon R5 AF Menu Page 4
  • 1:11:07 – Canon R5 AF Menu Page 5
  • 1:35:58 – My Dual- Back-Button AF Setup
  • 1:39:19 – Speed Round Q & A
  • 1:41:44 – Rudy’s Photographer Pick
  • 1:44:50 – Outro (no typo, they called it that way)

Enjoy the video.