Nikon Working On Improved Diffractive Optical Technology

Nikon Working On Improved Diffractive Optical Technology

Diffractive Optics and their use in constructing compact photographic lenses have become their own mini arms race over the last few years, with Canon’s DO, and Nikon’s PF lenses leading the pack in innovation. Simply put the use of diffractive optics allows the manufacture of much smaller lenses of a given focal length than would be possible without the use of diffractive optical technology (check out our knowledge base article entitled: What are Diffractive Optics? for a full explanation).

The nature of the industry and the increase in the use of diffractive optics of course means that manufacturers are constantly having to work on improvements to their chosen implementation of the technology; As such we can exclusively now reveal the latest diffractive optical element design from Nikon, surely destined for use in their next generation of PF lenses.

PROBLEM TO BE SOLVED: To provide a diffraction optical element that achieves high diffraction efficiency.

The document in question, published in late December 2016, describes the design of a new diffractive optical element and details how the diffractive efficiency of the element largely depends upon the design of the lattice through which the incoming light must pass:

A cross section of the new design showing the repetition of the diffractive lattice used for maximum efficiency.

A diffraction optical element is an optical element using diffraction which arises when light passes a lattice with periodicity.
Diffraction efficiency of the diffracted light of each degree is dependent on structure of a lattice.
It constitutes so that one wave (when using the primary diffracted light) of optical path difference may arise at the both ends of one lattice by the diffraction optical element making the maximum diffraction efficiency of the diffracted light of the degree to be used, for example, providing a triangular blaze in a lattice. In order to produce such the optical path difference, it is not necessary to necessarily make lattice form into a triangular blaze. For example, it is also possible to constitute from applying voltage to the liquid crystal layer inserted into two electrodes so that the inclination of a liquid crystal element may be changed and the optical path difference may be generated at the both ends of this liquid crystal layer

The document goes on to lay out an overview of two proposed manufacturing processes for the new element:

The  first proposed manufacturing process for the element, constructed by dipping optical material into various liquids.

The second manufacturing method involves spraying the components as opposed to dipping them.

Finally the document includes another view of the completed new element, showing the layered nature of the manufacturing process:

The completed element with all its layers combined.

A recent Nikon patent detailed the design of a new 24-70mm f/2.8E PF ED lens which could conceivably contain an element featuring this new design, hopefully we will be seeing more practical applications of diffractive optics in the near future.