Fresnel lens sidewall design for imaging optics

Abstract

We developed a ray tracing simulation tool for imaging systems including a Fresnel lens with a quasi-arbitrary sidewall structure. One issue with Fresnel lens is that noise in the image plane can appear from rays passing through or reflected at its sidewalls. One way to reduce it is to modify the orientation of the sidewalls so that rays will not reach the image plane. To find the best sidewall orientations, we developed a method where locally, a sidewall can freely be oriented. We could then derive the best modulation scheme for each Fresnel lens sidewall. In the case of a single imaging Fresnel lens, relative parasite noise intensity could mostly be prevented. To experimentally check our method, snapshot images were taken with single Fresnel lenses and a single spherical lens. No noticeable differences in image quality could be observed using a standard C-MOS camera. However, parasite noise could experimentally be detected with a Fresnel lens prototype when using a very high-dynamic range C-MOS camera.

Research on Virtual Reality Head-Mounted Displays based on MEMS Technology

“…The majority of virtual reality headset optics on the market currently feature a separate aspherical lens or a separate Fresnel lens. In virtual reality headsets, when using a single aspherical lens, the aspherical lens needs to be thicker and the overall weight of the headset heavier if it is to satisfy the image quality and reduce the impact of aberrations on the image [15][16][17]. The Fresnel lens produces a large amount of stray light during imaging when a Fresnel lens is applied exclusively because of its properties, which is difficult to eliminate through a single lens [18].…”

P‐42: High Efficiency VR Optical System

“…The first two optical systems always have heavy and bulky headset-type hardware. The last one can get a thin and lightweight glass-type hardware, but due to the energy loss during multiple refractionreflection, the optical efficiency of the whole optical system is very low (usually lower than 20%) [ [3][4]].…”

Fabrication of high-aspect-ratio SiO2 nanopillars by Si thermal oxidation for metalenses in the visible region

“…Fresnel lenses are thinner than bulk lenses because they are concentrically serrated, 2) but there are problems such as the deterioration of the imaging efficiency due to diffraction, making them unsuitable for camera applications except for specially designed ones. 3) Conversely, as a lens that positively utilizes the effect of diffraction, there is a diffractive lens represented by a Fresnel zone plate. [4][5][6] However, due to disadvantages such as an image blur caused by the 0th-order diffracted light, its use is limited to being incorporated as part of the conventional lens system.…”