OFILM successfully developed a new generation of VR Pancake optomechanical modules

As consumers put forward higher requirements for VR's lightness, imaging quality, and wearing experience, the Pancake solution will be more widely used in the future and has become the main layout direction of various manufacturers.

According to the official account of OFILM, OFILM has successfully developed a new generation of VR Pancake optomechanical modules. The product adopts a folded optical path 3P lens design and uses curved film technology. It has the advantages of short overall lens length, short-sightedness adjustment, no change in refractive adjustment FOV, low dispersion, and high PPD (pixel density), which can greatly reduce the weight of VR headsets. and volume.

According to the official introduction, compared with traditional aspheric lenses and Fresnel lenses, OFILM VR Pancake optical module has achieved a series of major breakthroughs in thinning, imaging quality, and adjustable diopter, as follows:

Short shot total length: Traditional VR lenses use aspherical lenses or Fresnel lenses, and the optical system has a back focal length, resulting in a total lens height > 25mm. OFILM adopts a folded optical path design, and the short back focus design brings a shorter total lens length (20mm), making VR thinner and lighter.

Myopia adjustment: The module uses moderate ring adjustment to achieve 50°~500° myopia adjustment, and myopia patients can focus clearly without wearing glasses.

No change in refractive FOV: Using O-Film VR Pancake 3P lens design, the difference in FOV corresponding to different diopters (0.5D~5D) is less than 0.2 degrees, and the size of the screen seen by users with different degrees is the same, and there is no need for post-processing screen adjustment due to changes in viewing angle, reducing system calculation energy consumption.

Low dispersion: In Traditional 3P Pancake, the dispersion is as large as 100~200um. OFILM VR Pancake lens design adopts a 3P structure and uses low-dispersion materials to reduce the Lateral color to 9.9um (<1 pixel), without post-processing color correction, reducing the CPU power consumption of the whole machine.

Comparison of dispersion effects
High PPD (pixel density): The module uses a single-eye 2K screen and is equipped with the O-Film VR Pancake 3P lens design, which can increase the PPD to 25, the overall image is more delicate, and the resolution is improved.

PPD (pixel density) effect comparison chart

The Pancake (folding optics) solution uses multiple re-entries of polarized light to achieve light transmission and viewing angle magnification in a narrow space. At present, the two-piece Pancake is the mainstream, mainly due to its low cost and high controllability. , the imaging effect is also quite guaranteed, and the overall technical solution is relatively mature. Compared with the Fresnel lens solution, the advantages of Pancake are mainly reflected in the lighter and thinner equipment (the weight of the VR head-mounted display of the Pancake / Fresnel lens solution is generally 180~200g / 400~500g, the thickness is generally 30-40mm / 70-80mm), the visual Higher field angle (unlimited panel resolution, theoretical field of view up to 200°), support for diopter adjustment (myopia friendly) . In terms of production, Pancake mainly has low optical efficiency (theoretical efficiency is 25%, practical application is 13~16%), high design threshold (multiple design parameters, multi-performance balance), low production yield (optical film technical difficulty) High, assembly and lamination production yield) and other issues, further optimization directions include system design, lens technology, variable focus, etc.

According to OFILM, the company has a number of VR/AR projects under fixed-point development, and some projects have been successfully transferred to mass production. Customers and partners include well-known domestic and foreign manufacturers.

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