Canon Patent Application: Diffractive Optics Elements

In this patent application, Canon describes a different method of manufacturing diffractive optical (DO) elements using a resin mold and having a high level of optical performance.

We are led to understand that a DO element right now is an expensive addition to the lens.  Cheap mold based mass production of DO elements would go a long way of bringing high quality DO elements to many lenses, and would certainly help make lenses smaller than what they are currently.

DO elements allow lens designers to bend light at stronger angles. The specialized grating pattern corrects for wavelengths of light bending at different angles causing chromatic abberations.  Chromatic aberrations are more pronounced as you increase the amount the light is bent.  The level of chromatic aberration correction that a DO element can do is better than even a fluorite element.  This allows lens designers to "squish" the lens together more making the lens more compact. It traditionally doesn't save much in terms of weight with the exception of a smaller amount of materials used for the lens housing, because you still have the same number of elements as you would without using DO but it certainly reduces the size.

Japan patent application  2019-117421