VR Lens Barrel Fill Layer for Back Focus Length Compensation
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Solution Overview
Problem
In virtual reality display devices, the difference in back focus lengths (BFL) between left and right lens barrels due to manufacturing tolerances and assembly inaccuracies leads to varying virtual image distances (VID), causing poor superposition of virtual images and user fatigue, making it difficult to maintain a clear three-dimensional visual scene.
Innovation Solution
The introduction of fill layers between the lens holders and lenses in the virtual reality display device, which are adjusted to match a target distance, ensures consistent virtual image distances across both lens barrels, thereby improving the display effect by minimizing differences in BFL and VID.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If manufacturing tolerances and assembly inaccuracies are present in lens barrels, then production efficiency and ease of manufacture are improved, but the back focus lengths differ between left and right lens barrels, causing varying virtual image distances and poor superposition of virtual images
Solution Approach 1:
The patent introduces fill layers with adjustable thicknesses between the lens holders and lenses to compensate for variations in back focus lengths. By changing the thickness parameter of the fill layers, the virtual image distances are adjusted to be consistent, resolving the contradiction between ease of manufacture and manufacturing precision without requiring tight tolerances on the lens barrel components.
2Manufacturing precision
If fill layers are introduced to adjust back focus lengths, then virtual image distance consistency is improved, but device complexity increases due to additional components and assembly steps
Solution Approach 1:
The patent applies fill layers locally between the lens holders and lenses, adding complexity only where needed to compensate for back focus length variations. This localized approach adjusts virtual image distances without significantly increasing overall device complexity, as the fill layers are simple components integrated into existing structures.
3Manufacturing precision
If tight manufacturing tolerances are enforced to maintain consistent back focus lengths, then virtual image superposition quality is improved, but production cost and manufacturing difficulty increase
Solution Approach 1:
The patent changes the approach from controlling back focus length through tight manufacturing tolerances to adjusting virtual image distance through fill layer thickness. This parameter change allows standard manufacturing tolerances to be used while achieving consistent virtual image distances, thereby improving ease of manufacture without sacrificing superposition quality.
Data Source
AI summary
Embodiments of this application relate to a virtual reality display device. The virtual reality display device includes a left lens barrel and a right lens barrel; the left lens barrel includes: a left lens barrel housing, a left display screen, and a left lens; the right lens barrel includes: a right lens barrel housing, a right display screen, and a right lens; an inner side of an opening portion of the left lens barrel housing includes a left lens holder; an inner side of an opening portion of the right lens barrel housing includes a right lens holder; a left fill layer is provided between the left lens holder and the left lens; and a right fill layer is provided between the right lens holder and the right lens.