Key Technology > Production Engineering Technologies > Molding Technologies
Enabling the Mass Production of High-Precision Aspherical Lenses and DO Lenses
Molding Technologies
Aspherical lenses have curved surfaces with continuously varying degrees of curvature across the diameter of the lens.DO (Diffractive Optics) lenses, on the other hand, have fine structures designed to diffract light on the surface. Canon proprietary technologies employed in the manufacture of aspherical lenses and diffractive-optical elements include mold-making technology, considered to be the most difficult technology used in lens production. Canon uses these manufacturing techniques selectively based on the precision, diameter, and cost considerations required for each lens in response to user needs.
Photo-replication method
In photo replication, a UV hardening resin is placed on an aspherical lens surface to transfer the mold shape, after which the resin is allowed to harden. An aspherical mold forms the resin into an aspherical lens, whereas a mold processed from a concentric Fresnel grating results in the creation of a diffractive-optical element. After years of research into mold-making techniques to fabricate finely shaped molds as well as the characteristics and physical properties of resins, Canon has perfected a technique for the precision control and transferring of fine shapes at the nanometer level, making possible the manufacture of a wide variety of lenses.
Plastic molding method
Plastic molding involves pouring plastic into a finely crafted mold to create a lens. This technology is based on numerous innovations that ensure precise and stable molding. Used to produce aspherical lenses for compact cameras, this technique also contributes to the realization of compact product sizes.
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Large-Diameter Lens |
Roof Prisms (for Lens-Shutter Cameras and Digital Cameras) |
Toric Lenses |
Glass molding method
Molds for Manufacturing Aspherical Lenses
Glass molding employs high-precision aspherical molds, which are pressed directly on glass to shape it into lens elements. Based on studies of glass materials and mold materials, Canon conducted simulations for variations in temperature and size to create molds that ensure consistently accurate performance even at high temperatures (with precision on the order of 0.3 µm or less and surface roughness of 0.02 µm). Lenses manufactured from these glass molds have found wide application due to the flexibility they offer with respect to refractive index and other optical parameters.
