Designing A New Kind of Holographic Lens
The road to market acceptance of smart glasses has been a bumpy one, but augmented reality smart glasses are evolving. Companies like North (formally Thalmic Labs) are delivering slick and stylish smart glasses that do amazing things. Called Focals by North, these smart glasses are virtually indistinguishable from regular eyeglasses but let users check text messages, emails, or call up directions from Alexa.
Putting the “Wear” in Wearables
Early versions of Augmented Reality glasses were often criticized for their styling and lack of respect for privacy. North, however, designed a system that reflects images on to the user’s retina without any visually obvious components, so no one is aware that the glasses are smart. And just like designer glasses that you would buy at the optometrist, the lenses are curved and not flat for a more flattering design.
Overcoming Optical Challenges
Designing lightweight, stylish mixed reality glasses is not an easy task. Luminit has a long history of creating holographic thin film optics for augmented and virtual reality head up displays so we understood the challenges any wearables company would face. Augmented Reality glasses need to be truly transparent and blend the digital world without interfering with the real world. Surface relief micro-optics are too hazy, and nano-optics are too costly to manufacture at consumer volumes. North needed a highly transparent, diffractive optic with lower index contrast and higher thickness recorded on transparent photopolymer film. Any holographer will tell you that Holographic Optical Elements (HOEs) exhibit these properties; however, no one had the capability to mass produce volume HOEs. To produce Focals by North, Luminit combined its expertise in HOEs with our thin film roll-to-roll mass production capabilities and provided North with Transparent Holographic Components™ (THCs), holograms recorded on photopolymer film that met their requirements of no added weight and images only visible to the users.
Luminit can mass produce holograms on a roll-to-roll platform at high volumes and low cost, making it ideal for AR smart glasses, Head-up Displays and other Augmented Reality devices. Transparent Holographic Components™ use Holographic Optical Elements to direct light replacing conventional optics that can be bulky and heavy. These thin film products mimic the properties of positive optical lenses that can collimate or even focus light sources, thus replacing convex lenses, mirrors and gratings that made smart glasses “not so smart looking.” These holograms have thick Bragg properties that are wavelength and angle selective with very low scattering, low haze and transparency above 90%. THCs eliminate prism-based optics with a see-through technology that allows the images to be viewed on axis, and users do not need to visually toggle from reality to augmented reality. THCs also allowed Focals by North to have a large virtual image size with a FOV of 15 degrees. By using Luminit THC technology, North was able to uphold their strict aesthetic principles and create AR glasses that are slim, lightweight and stylish.
