Binocular Display Virtual Focal Point Divergence
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Solution Overview
Problem
Planar waveguide display devices require users to focus at infinity to perceive the display clearly, which can be uncomfortable and makes it difficult to visually separate display elements from the external scene, as they are inherently collimated and share the same focus.
Innovation Solution
A binocular display device with two ocular assemblies, each comprising an outer optical part with positive optical strength for receiving external light and directing it to a transparent planar waveguide, and an inner optical part with negative optical strength to impose divergence on the collimated display light, creating a virtual focal point common to both eyes, allowing for 3D viewing by applying parallax through offset or position shifts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the display light is kept collimated for clear perception, then the display clarity is improved, but the user comfort deteriorates when focusing on external scenes at different distances
Solution Approach 1:
The patent applies different optical treatments to different light paths: the display light path receives collimation treatment through the waveguide for clear perception, while the external light path maintains its original divergence characteristics for comfortable viewing at various distances. This local differentiation resolves the contradiction by allowing each light type to have optimal optical properties independently.
Solution Approach 2:
The optical system is segmented into separate handling for display light and external light. The waveguide structure separates these light paths, allowing the display light to be collimated while external light passes through with minimal distortion, enabling simultaneous optimization of display clarity and viewing comfort.
2Device complexity
If all display elements share the same focus at infinity, then the display structure is simplified, but the visual separation and distinction of separate display parts becomes difficult
Solution Approach 1:
Different visual properties are applied to different display elements through the waveguide. By controlling the coupling and decoupling points of light within the waveguide, each display element can be presented at different virtual depths, creating visual separation and distinction while maintaining a relatively simple waveguide structure.
3Measurement precision
If the display light is collimated for clear perception, then the display clarity is improved, but the ability to create 3D depth perception deteriorates
Solution Approach 1:
The patent introduces dynamic focal adjustment capability through variable focus lenses or tunable optical elements in the ocular assemblies. This allows the display to switch between collimated (2D) and divergent (3D) light paths, enabling both clear 2D display and immersive 3D depth perception depending on the operational mode selected.
Solution Approach 2:
The system can periodically alternate between different focal states or use sequential scanning of focal planes to create the perception of depth. By rapidly switching between different virtual image distances, the human visual system integrates these changes to perceive 3D depth while maintaining overall display clarity.
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 comfortable 3D viewing by allowing users to maintain focus on the external scene while superimposing display information as a 3D image, with the virtual focal point adjustable to control depth perception, and minimizes distortions in the external scene.
Implementation Method 1
an outer optical part having a positive optical strength arranged for receiving external light from an external scene and for directing the result to a transparent planar waveguide display part of the device
Implementation Method 2
a transparent waveguide display part arranged for outputting through a planar surface substantially collimated display light guided thereto by the waveguide display part and for transmitting through the planar surface the external light directed thereto
Implementation Method 3
an inner optical part having a negative optical strength arranged for receiving both the external light and the substantially collimated display light from the waveguide display part, and for imposing a divergence on the received display light to generate a virtual focal point
Data Source
AI summary
A binocular display device comprising two ocular assemblies (1A, 1B) to be worn by a user concurrently with one respective ocular assembly at each eye. Each ocular assembly comprises an outer optical part having a positive optical strength (2A, 2B), an inner optical part (4A, 4B) having a negative optical strength and a transparent slab waveguide display part (3A, 3B) in between them. Substantially collimated display light is output from the waveguide for display, and external light of an external scene is transmitted through the waveguide from the outer optical part for viewing concurrently with the display light. The inner optical part imposes a divergence on the received display light to generate a virtual focal point (f) substantially common to each ocular assembly. In use, an image conveyed by the display light is superimposed on the external scene as a three-dimensional (3D) image when viewed through the binocular display device.