Egami (translated) spotted another patent filed by Canon. It is for a 400mm f/4 lens with diffractive optical elements (to reduce flare).

Patent description (machine translated):

• Patent Publication No. 2013-64858
  • 2013.4.11 Release Date
  • Filing date 2011.9.16
• Example 1
  • Focal length f = 392.12mm
  • Fno. 4.12
  • Half angle of ω = 3.16 °
  • Image height Y = 21.64mm
  • 262.14mm length lens
  • BF 69.97mm
  • Two fluorite
• Materials and anomalous partial dispersion DOE to use, reduce the chromatic aberration
• Refractive power of the diffractive surface
  • Strong, but can reduce the chromatic aberration of the element itself, flare increases
  • The weaker, other optical element DOE play a role
• Refractive optical unit
  • DOE anomalous partial dispersion and bonding materials
  • DOE aspherical surface on the opposite side of the
• Vibration control
• Inner Focus

[via Egami]

Egami spotted another patent filed by Canon. The patent refers to s 50 mm F1.4 , 50 mm F1.2 , 45mm F1.6 and 60 mm F1.8 lenses, and describes an apochromatic design that aims to reduce chromatic aberration.

Patent description (machine translated):

• Patent Publication No. 2013-57802
  • 2013.3.28 Release Date
  • 2011.9.8 filing date
• Example
  

  Example

  	Focal length	Fno.	Angle of view	Focus
  One	51.7	1.45	45.4	Floating rear focusing +
  Two	51.7	1.45	45.4	Fed whole
  Three	51.7	1.25	45.4	Floating rear focusing +
  Four	51.7	1.25	45.4	Fed whole
  Five	45.0	1.6	51.4	Fed whole
  Six	60.0	1.85	39.7	Fed whole

• In many large-diameter Gaussian secondary spectrum of axial chromatic aberration
  • This problem occurs when using glass and others with the same Abbe number, a lens that is different partial dispersion ratio
  • When used in a positive lens lanthanum flint glass small partial dispersion ratio
  • When used in a negative lens of flint glass titanium large partial dispersion ratio
• Canon patent
  • Using a lens with a partial dispersion ratio appropriate correcting the axial chromatic aberration secondary spectrum
  • The concave lens surface adjacent to the aperture, coma aberration correction, the sagittal flare

[via egami]

Egami (translated) found a patent filed by Canon for a 14mm f/2.8 lens with a new anti-reflective coating, Subwavelength Structure Coating. This method optimizes the refractive index and allows for a thinner anti-reflective film.

Appears as if Canon is working on a successor of the EF 14mm f/2.8L II USM lens (price & specs).

Patent specification (machine translated):

• Patent Publication No. 2013-47780
  • 2013.3.7 Release Date
  • Filing date 2011.7.26
• Example
  • F = 14.3mm focal length
  • Half angle ω = 56.6 °
  • Fno. 2.89
  • 14 images in 10 groups lens configuration
• Canon patent
  • Antireflection film which is excellent in productivity and reflectance characteristics
  • The refractive index of the substrate (original surface of the lens) is 1.65 to 2.20
  • Consists of three layers, the ratio of the refractive index change with a three-layer
  • The third layer
    • Average roughness of less than 400nm pitch structure
    • By continuously varying the ratio of the space-filling structure uneven, changing the refractive index
    • After drying, the film is immersed in hot water and applied to the second layer solution (containing aluminum oxide) by spin coating, plate-like crystals deposited on the surface
  • If spin coating of the wet process, excellent in productivity can be realized a uniform thickness
  • Little change in the characteristics even if there is variation in thickness

 

Egami (translated) spotted a Canon patent concerning a second row of electronic contacts on the lens mount. The patent suggests the second row of contacts is dedicated to the video signal, avoiding loss of signal strength could be the reason (the video signal needs more power supply).

• Patent Publication No. 2013-21391
  • 2013.1.31 Release Date
  • 2011.7.7 filing date
• Canon patent
  • In addition to the conventional first electronic contact, provided new second electronic contacts
  • Contact each other first and second non-overlapping so that
  • Corresponding to the new system
    • In addition to the video sync signal
    • In the serial clock, eliminating the need for transformation of the communication level
    • Because the focus of video requires a larger power supply