Surface Lenses and Light-Scattering Structures for HMD Image Depth
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Solution Overview
Problem
Current wearable displays struggle to seamlessly overlay virtual images onto a user's real-world view while maintaining clear visibility of the surroundings, especially in dynamic environments, due to limitations in light scattering and collimation technologies.
Innovation Solution
An optical system comprising a transparent element with light-scattering structures on one surface and surface lenses on the other, illuminated by a rastering light source to collimate light towards the viewer's eye, allowing for the integration of virtual images within the wearer's field of view without obstructing the real-world environment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a transparent element with light-scattering structures is used to overlay virtual images, then virtual image visibility is improved, but real-world view clarity deteriorates
Solution Approach 1:
The transparent element is divided into multiple light-scattering structures (microlenses, diffusers, or prisms) that are spatially distributed across the element. Each structure directs light from specific virtual image points to the viewer's eye while allowing other regions to transmit real-world light, thereby segmenting the light manipulation function across multiple discrete elements to simultaneously achieve virtual image visibility and real-world view clarity
Solution Approach 2:
Different regions of the transparent element have different optical properties - areas with light-scattering structures enhance virtual image visibility while areas with minimal or no structures maintain real-world view clarity. The density, size, and type of light-scattering structures are locally optimized based on the desired virtual image placement and viewing requirements
2Ease of manufacture
If light-scattering structures are added to the transparent element, then virtual image formation is improved, but device complexity increases
Solution Approach 1:
The light-scattering structures are integrated directly into the transparent element itself, merging the functions of the transparent substrate and the light-scattering components into a single unified element. This eliminates the need for separate transparent element and light-scattering structure components, reducing assembly complexity while maintaining virtual image formation capability
Solution Approach 2:
The optical properties of the transparent element are modified by varying parameters such as the refractive index, size, shape, and distribution density of the light-scattering structures. By adjusting these parameters, different virtual image characteristics can be achieved without changing the fundamental structure of the device, thereby managing complexity through parameter optimization rather than structural complexity
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
Enables the simultaneous observation of real-world surroundings and virtual images, enhancing user interaction and information delivery in wearable computing devices by providing clear, unobstructed views and customizable image placement within the user's field of vision.
Implementation Method 1
A corresponding plurality of light-scattering structures are located on a distal surface of the transparent optical element
Implementation Method 2
Each surface lens is optically coupled to at least one respective light-scattering structure so as to collimate light scattered therefrom towards a viewing location
Data Source
AI summary
An optical system is provided with a transparent element having a proximal surface on one side and a distal surface on an opposite side. A plurality of light-scattering structures is formed in the distal surface. A positionally-corresponding plurality of surface lenses is provided on the proximal surface. The light-scattering structures and the surface lenses may be arranged in a slightly angled or offset square array relative to a side surface of the transparent element. A rastering, collimated light source, directs a beam of light roughly in the plane of the transparent element towards individual light-scattering structures. The light-scattering structures scatter at least a portion of the light towards the corresponding surface lenses, which may collect and collimate the light towards a viewing location. The optical system may be incorporated into a head-mounted display (HMD).