Secondary Lens Array for Thin HMD Imaging
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Solution Overview
Problem
Current head-mounted displays (HMDs) for virtual reality face challenges in achieving sharp, high-resolution imaging with a large field of view due to tradeoffs between maximum screen pixel utilization, sharp optical performance, and very large field of view, resulting in suboptimal imaging quality.
Innovation Solution
Incorporating a secondary array of optical elements between the display and the primary lens array, which includes arrays of tapered optical fibers, plano-concave field lenslets, bi-convex lenslets, or plano-convex lenslets, to concentrate elemental images and enhance pixel utilization and optical performance, allowing for a thin, lightweight form factor with a wide field of view and high angular resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional optics are used in HMDs, then the device can provide basic imaging functionality, but the HMD becomes bulky, heavy, and has limited field of view
Solution Approach 1:
The patent divides the optical system into multiple discrete lens arrays (primary lens array, secondary lens array, and optional tertiary lens array), each performing specific optical functions. This segmentation enables the system to achieve compact form factor while maintaining high-quality imaging across wide field of view by distributing optical processing across multiple specialized components rather than relying on a single bulky optical element.
Solution Approach 2:
The patent implements nested lens arrays where a secondary lens array is positioned within the optical path of the primary lens array, and optionally a tertiary lens array is nested within the secondary. This nested configuration allows multiple optical processing stages to be integrated in a compact volume, achieving high pixel utilization and sharp imaging without increasing overall device size.
2Length of moving object
If near-eye light field displays are implemented, then the HMD size is reduced to thin and lightweight, but tradeoffs arise in achieving sharp high resolution imaging with large field of view
Solution Approach 1:
The patent applies local quality by using heterogeneous lens arrays where different lens elements have different optical properties optimized for their specific positions and functions. The primary, secondary, and tertiary lens arrays each have tailored lens parameters (focal lengths, curvatures, spacing) that are locally optimized to handle specific portions of the optical path, enabling sharp imaging across the entire field of view while maintaining thin form factor.
Solution Approach 2:
The patent transitions from conventional 2D display imaging to 4D light field imaging by adding two spatial dimensions through the lens array configuration. The multiple lens arrays create a three-dimensional light field distribution that preserves angular and spatial information, enabling sharp high-resolution imaging across wide field of view in a thin profile by utilizing the additional optical dimensions.
3Measurement precision
If maximum screen pixel utilization is achieved, then imaging resolution is improved, but field of view is reduced
Solution Approach 1:
The patent merges the functions of multiple lens arrays (primary, secondary, and tertiary) to simultaneously achieve high pixel utilization and wide field of view. The combined optical processing of these arrays redistributes light from the display across the full field of view while maintaining high angular resolution, effectively multiplying the pixel utilization benefit across the entire viewing area rather than sacrificing field of view for resolution.
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
This configuration enables HMDs to provide simultaneous thin form factor, wide field of view, sharp optical imaging, and high-quality angular resolution, overcoming previous tradeoffs and improving user experience in virtual reality applications.
Implementation Method 1
a secondary array of optical elements between the display and the primary lens array, each optical element of the secondary array to concentrate a particular elemental image from the display to the receiving zone of a corresponding lens of the primary lens array
Implementation Method 2
Incorporating a secondary array of optical elements between the display and the primary lens array, which includes arrays of tapered optical fibers, plano-concave field lenslets, bi-convex lenslets, or plano-convex lenslets
Data Source
AI summary
Systems, devices, and techniques related to thin form factor head mounted displays and near light field displays are discussed. Such devices may include a display to present elemental images, a primary lens array in an optical path between the display and a viewing zone of a user, the primary lens array to magnify elemental images to a viewing zone, and a secondary array of optical elements between the display and the primary lens array to concentrate elemental images from the display to the primary lens array.