Question

What is the optical principle of EDOF lenses?

Hint:

EDOF lenses use wavefront shaping and aspheric designs to provide an extended focal range, minimizing visual disturbances such as halos or glare commonly seen with multifocal lenses.

Answer 1

The optical principle of EDOF lenses is based on the creation of a extended range of focus through a combination of optical design strategies. Unlike traditional monofocal lenses, which focus on a single point, EDOF lenses extend the focus to allow for clearer vision at multiple distances. The two primary optical principles used to achieve this are:
1. Wavefront Shaping:
- EDOF lenses utilize wavefront shaping technology, where the lens is designed to manipulate light in a way that produces a continuous range of focal points. This process involves creating an elongated focus, typically around the intermediate distance, which provides a better depth of field.
- This wavefront shaping helps in achieving a smooth transition between distances, reducing the abrupt changes in vision that can occur with traditional multifocal lenses.
2. Aspheric Surface Design:
- EDOF lenses often have an aspheric design, meaning the curvature of the lens is altered to reduce spherical aberration. This helps to maintain image quality across different distances.
- The aspheric surface also contributes to reducing glare and halos, which are common issues with multifocal lenses. This design allows the lens to focus over a broader range, especially for intermediate vision.
3. Non-Diffractive Optics:
- Unlike traditional multifocal lenses that use diffractive optics to split light into multiple focal points, EDOF lenses typically rely on non-diffractive optics to elongate the focal range without compromising the quality of vision at any distance.