Folded VR Optical Layout for Wide FOV and Longer Eye Relief
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing virtual reality (VR) products with folded optical paths (Pancake) have an eye relief of 13 mm to 15 mm, which is inadequate for myopic users wearing glasses, affecting their experience.
Innovation Solution
An optical system with a dual-optic structure, incorporating a polarizing transflective film, phase retardation film, and transflective film, configured with aspheric surfaces and a folded optical path, achieving ultra-short focal length, total track length, and wide field of view (FOV) with a large eye relief.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a folded optical path (Pancake) is used to achieve wide FOV and compact size, then the field of view is improved and device volume is reduced, but the eye relief becomes insufficient (13mm to 15mm) for myopic users wearing glasses
Solution Approach 1:
The optical system is divided into multiple optical elements including a first aspheric lens, a second aspheric lens, and a third aspheric lens arranged in sequence. Each lens is optimized with specific curvature parameters to independently control different aspects of light path, enabling the system to achieve both wide FOV and sufficient eye relief (15mm to 25mm) simultaneously
Solution Approach 2:
The patent introduces a polarizing transflective film that redirects light in a different spatial dimension, creating a folded optical path that extends the effective optical length without increasing the physical device volume. This dimensional transformation allows the system to maintain compact form factor while providing adequate eye relief for glasses wearers
2Volume of moving object
If the focal length is reduced to achieve ultra-short focal length for compact display, then the device volume is reduced, but the optical performance and field of view become compromised
Solution Approach 1:
The patent employs three aspheric lenses with specifically designed curvature parameters (K1, K2, K3) to correct optical aberrations and expand the field of view. The aspheric surfaces enable the system to achieve wide FOV (100° to 110°) while maintaining ultra-short focal length (26mm to 30mm) and compact device volume
Solution Approach 2:
The optical system uses a composite structure combining different aspheric lens elements with optimized refractive indices and curvature parameters. This composite optical design enables the system to achieve both ultra-short focal length for compactness and wide field of view for immersive display experience
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides an optical system with a wide FOV of 100° to 110° and an eye relief of 13 mm to 21 mm, improving user experience, especially for myopic users wearing glasses, while maintaining a compact size.
Implementation Method 1
a polarizing transflective film, a phase retardation film and a transflective film
Implementation Method 2
a phase retardation film
Implementation Method 3
The first optic includes a plane surface and a first aspheric surface, and the second optic includes a second aspheric surface and a third aspheric surface
Implementation Method 4
a polarizing transflective film, a phase retardation film and a transflective film
Data Source
AI summary
An optical system and a display device are provided. The optical system includes an optic group, a polarizing transflective film, a phase retardation film, and a transflective film. The optic group includes a first optic and a second optic; the polarizing transflective film and the phase retardation film are on one side of the optic group, the transflective film is on the other side of the optic group. The first optic includes a plane surface and a first aspheric surface having a curvature radius of −120 mm to −140 mm, the second optic includes a second aspheric surface having a curvature radius of −175 mm to −185 mm and a third aspheric surface having a curvature radius of −100 mm to −110 mm; a focal length of the optical system is 26 mm to 30 mm, an effective aperture of the optic group is 55 μm to 58 μm.