VR Display Optical System Using Polarization to Reduce Ghosting
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Solution Overview
Problem
The 'ghosting' phenomenon in VR optical systems significantly reduces image contrast and clarity, especially at full field of view angles, necessitating a solution to improve image quality.
Innovation Solution
An optical system design incorporating a beam splitter, phase retarder, polarization reflection element, and optimized lens group with specific thickness ratios and configurations, including a protective glass, to manage optical path differences and reduce ghosting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional lens design is used in VR optical system, then the structure is simple, but ghosting phenomenon occurs and image quality deteriorates
Solution Approach 1:
The optical system is divided into multiple functional components: beam splitter, phase retarder, polarization reflection element, and lens group. Each component performs a specific function to collectively solve the ghosting problem while maintaining manageable complexity.
Solution Approach 2:
A phase retarder is introduced as an intermediary element between the beam splitter and the polarization reflection element. This intermediary component modifies the polarization state of light to prevent ghosting without requiring complete redesign of the entire optical system.
2Manufacturing precision
If lens thickness is not optimized, then manufacturing is easier, but optical path difference increases and ghosting worsens
Solution Approach 1:
The lens design optimizes specific parameters including thickness distribution, curvature radii, and refractive indices. By carefully selecting and adjusting these parameters, the optical path difference is controlled to minimize ghosting while keeping manufacturing within reasonable limits.
3Adaptability or versatility
If field of view angle is increased to full view, then coverage is improved, but ghosting phenomenon becomes more severe
Solution Approach 1:
The optical system employs components with spatially varying properties. The lens group has different curvature radii for different zones (first surface vs. second surface), and the polarization elements are positioned at specific locations to address ghosting issues that are more pronounced at certain field of view angles.
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 design enhances image quality in the full and edge fields of view by optimizing lens thickness distribution, reducing optical path differences, and minimizing ghosting, thereby providing a clearer and more accurate visual experience.
Implementation Method 1
a beam splitter, a phase retarder, a polarization reflection element are provided along a same optical axis
Implementation Method 2
the phase retarder is provided between the beam splitter and the polarization reflection element
Implementation Method 3
a beam splitter, a phase retarder, a polarization reflection element are provided along a same optical axis
Implementation Method 4
the lens group at least includes a first lens, and the first lens is provided on a side of the beam splitter away from the phase retarder
Data Source
AI summary
An optical system, including: a beam splitter, a phase retarder, a polarization reflection element, a lens group, and a second lens. The beam splitter, the phase retarder and the polarization reflection element are provided along a same optical axis, and the phase retarder is provided between the beam splitter and the polarization reflection element; the lens group and the second lens are provided along the optical axis, the lens group at least includes a first lens, and the first lens is provided on a side of the beam splitter away from the phase retarder, and the first lens satisfies: 0.7≤|H1−H0/H2−H0|≤3.