Apple industry analyst Ming-Chi Kuo says Apple is planning to use a hybrid Fresnel lens design for its mixed reality headset, which would improve optical performance while also allowing for a broad field of view. The move would also keep the weight of the new headset at under 150 grams (around a third of a pound). Kuo’s remarks come in a new report shared by MacRumors.
Most virtual reality headsets employ Fresnel lenses to enable ultra-short focal lengths. Unfortunately, the technology, which was first used around 200 years ago to focus lighthouse beams, results in bulky headsets typically weighing in at 300-400 grams or more.
Mixed-reality headsets, such as the one said to be under development by Apple, can be thinner and lighter, as the lenses can be simpler with a smaller field of view (FOV) due to the less immersive experience compared to true virtual reality.
Kuo says Apple is attempting to use a hybrid Fresnel lens composed of three stacked Fresnel lenses to achieve a thin and light design providing enhanced optical performance.
Kuo says each headset uses a total of six Fresnel lenses (one stack of three per eye), using lightweight plastic lenses with customized materials and coatings to match the light transmission of glass.
The purpose of this design is to improve FOV and reduce weight and thickness. We believe that Apple will use a hybrid Fresnel lens design further to enhance the Fresnel lens’s optical performance (e.g., improve vignetting and optical artifacts), and each hybrid Fresnel lens comprises three stacked Fresnel lenses.
We believe that Apple’s design will achieve a better balance between HMD’s FOV and form factor.
The lenses are said to be supplied in the most part by Young Optics, although Genius Electronic Optical is providing some of the lenses. The lenses are not cheap, and will contribute greatly to the headset’s overall price, said to be somewhere in the $3,000 USD range.